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Another '03 Hemi "Losing power / cutting out" case

37K views 83 replies 13 participants last post by  crasher76 
#1 ·
I have an '03 Ram 2500 2wd, 5.7L Hemi, which has recently joined the club of trucks experiencing sudden power loss while driving. I bought this truck new, and it currently has right at 77,000 miles.

The problem is intermittent, but seems most likely to occur as part of my morning commute (cooler temperatures, higher humidity)

So far, it has happened somewhere around 8 or 10 different times. On my morning commute, it most typically happens when entering an interstate. I might accelerate up to 55-60 mph or so, then the accelerator pedal will start to feel "soft", as if I can tell it's about to cut out. The truck will then be non-responsive to throttle input, and will typically "jerk" on and off the power.

After 15-20 seconds or so of this behavior, the driveability will return to normal.

So far, this has only happened within 10 minutes after a cold start-up of the truck.

I am not experiencing a Check Engine Light.

I know that this type of problem is far from uncommon, but I have not been able to find a definitive fix for it, either.

The only attempts at corrective action that I've taken have been to remove and clean the throttle body, and to replace the air temperature sensor located in the intake tubing (between the air filter and the throttle body).

I hesitate to take it to the dealer when there is no CEL, and the problem does not occur 100% of the time.

If there is a "most likely cause", I will be happy to spend some time replacing sensors.

As I said before, I know that plenty of other people have experienced this kind of problem, but I'm not aware of a reliable solution.

Any help would be appreciated.

Steve.
 
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#2 ·
is it fully up to operating temp when this happens ? I'm thinking clogged cat and/or bad pre-cat O2 sensors
 
#3 ·
Add the ground wire from either battery or fender to the bolt on the throttle body, Use a minimum of 22 awg wire. sounds like a ground issue.
 
#4 ·
Thanks guys. I really need to get this problem solved. When it loses power, it loses virtually ALL power, as in it's unsafe to drive.

An additional ground wire to the TB is easy enough. I suppose the OEM design must ground the TB through the TB servo harness? Are there known issues with these servos having weak grounds?

As far as the 02 sensors, that seems like it could be a possibility, although I would hope that a bad 02 sensor would throw a code.

With respect to the catalytic converter, I don't see how a bad cat could cause an intermittent problem which quickly and suddenly clears up.

Steve.
 
#5 ·
clogged cats can act like that until they fully plug up, the you're done. Also, a bad O2 can cause issues like this long before it throws a code. They are wear items and generally should be changed @ 60K miles.
 
#6 ·
The accelerator pedal has a cable connected to the Accelerator Pedal Position Sensor (APPS), the APPS then develops a 0-5vdc signal to the PCM which in turn with all the other input signals sends a throttle signal to the ECT which is the throttle Body stepper motor. If you are physically feeling a change in the gas pedal then there is something wrong with the cable/APPS.
 
#7 ·
Does it ever act like its a manual trans like it wants to choke down? Mines done that a few times b4. Actually cut off chillin at a stop light one time. That was b4 my cam install too. My old service manager told me that in 03-4 timeframe, there was a line around the dealership for a re-flash of the Rams. Ive never had mine flashed but it hasn't done that in a couple years. And even b4 that it was only 6or so times in about a 3-4yr period.
 
#8 · (Edited)
Not a Hemi...

but sounds familiar to what I have.. see here:
http://www.dodgetalk.com/forums/showthread.php?t=385426
tonight I went to pick up a lawn mower. Truck behaved till I got back in our driveway.. Was using "Torque" on my phone to watch the O2 sensors since after this issue started eventually a high v. bank 1 sensor 1 code was thrown.. which I cleared t o"watch it"...

In driveway bank 1 sensor one pegged at high and didn't oscillate anymore..
Still no code but )2 bank 1 sensor 2 high voltage is now "pending"


Cause or effect??? Can an O2 sensor flood an engine.. which is what seems to be happening in these cases..

for later IF it is indeed a clogged CAT @40k miles..
;)

http://www.*************/f61/cat_clogged_over_heating-7522/index2.html

Cut it open and hallow it out. Weld it back shut. Make sure the welds are facing up towards the truck so no one can see it
sledge hammer, 2' punch, and a guy drunk enough or stupid enough to hold it up while I bash it with the sledge oughta do it
Or you can try the waterhose trick, seen it happen on a 98 RAM. Beat on the cat till you get some flow while idling, rev the truck up till they're good and hot then jam a water hose up there full blast. You should here the popping and cracking....... Then crank the truck back up and blow them out, this may take a few tries but it worked for us......
 
#9 ·
O2s supply the main input to the PCM to control fuel settings. They are very heat sensitive in that they only operate in a somewhat narrow band of temperature. Flooding and dumping fuel into the cats will kill them fairly quickly. This sounds like a bad wire, bad connection and/or a bad O2s.
 
#10 ·
What's maddening is that there have been plenty of similar cases of Ram trucks losing power, stalling, etc, but there does not seem to be a reliable solution.

I'm dropping it off at the dealer tonight, and will ask them to update all software and apply any TSB fixes before doing additional problem solving.

I am the one and only owner of this truck, which has 75,xxx miles now. It's been used, but not abused. These "ghost" problems are extremely frustrating.

Steve.
 
#12 ·
These "ghost" problems are extremely frustrating.

Steve.
now that is ironic.. Just tonight I was thinking my truck was "haunted".. well had to use it today and behaved well up until my return trip from the lumber store.. Started it's dogging/flat/kil/ trick. I'd pull over ,stop it and then restart.. Usually worked for a mile or 2. This time no luck.. Every stop was a nightmare. Finally turned off onto a side street. Shut it off and waited 5-10 min.. Listened to some really funny little ticking noises.. Like rain drops inside the engine.. Well started it up and drove fine for 5 more miles.. hung some drywall and drove another 5 miles home. Got in the driveway and started to play w/ "torque" program.. watching the )2 sensors.. post CAT had flat lined at 1V... pre-cat was doing its usual up and down swing.. I was getting bored watching nothing and the truck was idling fine in park. Decided to check out the help menu.. sure enough as soon as I left the O2 graph the engine started losing idol.. heading to stalling.. Oddly it never made it there and then just regained composure.. Of course fumbling around w/ the phone I never did see if I could at least guess if it was the O2 sensor or if the O2 sensor just followed the event.. Then the weirdest thing happened, my heater/ac blower motor just quit.. No speeds what so ever... AC was off at the time.. Shut the truck off and started it again.. Blower was now working.. Haunted I tell you... ;)
 
#11 ·
It has never died at a stop or in traffic, but the sudden power loss on the interstate is extremely dangerous. Twice within the last week, I have been forced to turn on my hazard lights while merging onto the interstate, as I simply had no power to accelerate.

The mechanical feel of the pedal doesn't change, only the fact that the engine will not respond to throttle input changes.

Steve.
 
#13 ·
Grounding issue, the tinkking noise is coming from I would guess a seriously over heated cat the other poster is experiencing limp mode.
 
#14 ·
Excellent discussion here! I'm sold on the idea of adding an additional ground from the TB to the engine to the chassis. Even if it doesn't fix the problem, it can't hurt.

With respect to the Limp Mode, are you saying that you think my issue (the original poster) is a Limp Mode problem, or that Jeffkrol's truck is going into Limp Mode?

The Torque app for Android looks like a great diagnostic tool. Unfortunately, in this case, I'm an iPhone user. I just started researching iPhone apps for the same kind of diagnostics. Any recommendations for iPhone?

Steve.
 
#15 ·
Jetmugg, yours sounds like it is going into Limp mode. Have you gotten any codes at all?
 
#16 ·
I have not gotten any codes. I took it to the dealer and had them apply 2 flash updates, one for the PCM, and one for the TCM.

Here's an oddball thought, related to a problem I had years ago. My wife once had a key made for this truck, and when she would use her key, the truck would stumble, barely idle, basically be undrivable. I didn't believe her at first, but when I tried the key she had made, sure enough, the truck drove like crap.

We had another key made, and the problem went away.

Is there a way for the ignition key to be triggering a limp mode? My everyday key is the original from December of 2002.

If this happens again, I think I'm going to try using "her" key.

Steve.
 
#17 ·
I have heard of keys not working, but not of the truck running poorly because of a key. Maybe someone knows about this happening.
 
#18 ·
It fell on its face again this morning while attempting to merge with interstate traffic. Drastic drop-off of power, then suddenly back on the power, accompanied by some "popping" out the exhaust. Still no codes. TB has been cleaned, intake air temp. sensor changed, brand new plugs, brand new plug wires, and computer flash updates are in effect.

I'll install a ground wire from TB to block and chassis tonight.
 
#19 ·
If the power dropped then came back it did not go into Limp mode. That would also explain why there are no codes. It's a electrical problem, hopefully the new ground wires will tell something.
 
#20 ·
popping from the exhaust is a pretty good indication you're dumping fuel. have you noticed mpg shifts? i know, with this being intermittent, it's probably not too noticeable. the pre cat sensor could very well be on the fritz. if you're merging, i'm assuming you're mid throttle gaining rpm. see if you can simulate this situation somewhere else. also, get under there and inspect the wires going to the sensor. go ahead and start soaking that senson in PB Blaster at night so if/when you have to change it, it doesn't give you fits trying to break it loose.
it sounds to me like an issue with the oxygen sensor seeing as how it repeats under a "load condition". temperature, rpm, exhaust velocities, all affect O2 sensor performance.
 
#21 ·
Wonder why there are no O2s codes, or misfire codes. Loss of major ground might be playing a role here.
 
#23 ·
bad pre-cat O2s don't always through a code. The OP won't answer the question on the engine temp though. If this occurs only after the truck come to full temp, I'd suspect pre-cat O2s. If it happens at any temp, I'd be thinking clogged cat or strange electrical issues like you mentioned
 
#22 ·
It's still on the original 2003 battery as well. Never any problem starting, so I don't suspect the battery cables.

It seems to happen most often when there's a lot of dew on the ground, high humidity, etc. This morning there was a light rain.

Steve.
 
#24 ·
There's another possibilty. Just because a battery can turn the truck over, that doesn't mean it's good. These things can do some pretty strange things when the battery isn't up to par.
 
#25 ·
To date, every time that this problem has occurred has been within 5-10 minutes after a cold startup. At that point in time, it's probably not 100% up to operating temperature, but is pretty close. Generally, this has occurred on my way to work in the morning, departing home at about 6:15 a.m.

Only on one occasion so far, has the problem happened after the truck has been parked at work all morning, and I'm going out for lunch.

After the loss of power occurs, and then clears up, the truck will drive normally until it is shut down, and allowed to cool all the way down.

What do you guys think of the possibility of EGR problems causing this type of issue?

Steve.
 
#26 ·
So, it comes up to temp, goes into closed loop, then stumbles. I'm still betting pre-cat O2s, with clogged cat being my 2nd choice.
 
#27 ·
Dropped it off at the dealer mid-morning, asking them to drive it when it's cold, and to hook up their scantool before heading out on the road. If it does it during the first 10 mins, they will see it. If it doesn't do it within 10 mins, try again in the morning.

The worst thing right now is that I've lost confidence in the truck. I am going to tow a trailer to the Bonneville salt flats in early September, towing my race vehicle. Racing at Bonneville has been a lifelong dream. I can't afford to have this truck let me down on this trip. I'm on the fence about buying a new truck at this point.

I talked to the guys in the service dept at the dealer, sharing every detail I could come up with. I think I have got them "in my corner" on this truck, we will see what they can come up with over the next few days.

Steve.
 
#45 ·
Dropped it off at the dealer mid-morning, asking them to drive it when it's cold, and to hook up their scantool before heading out on the road. If it does it during the first 10 mins, they will see it. If it doesn't do it within 10 mins, try again in the morning.

I talked to the guys in the service dept at the dealer, sharing every detail I could come up with. I think I have got them "in my corner" on this truck, we will see what they can come up with over the next few days.

Steve.
OK - in what might be a sign from above, I received a coupon in the mail yesterday for a Mopar battery (installed cost $99.95).

I will report if the problem has been eliminated with a battery replacement.

Steve.
What happened w/ the techs????
 
#28 ·
HAve you attempted a new battery, yet? A 2003 battery is a long life. My 2004 ram is quite possibly on the original MOPAR Battery, (Dealership or installer didn't mark battery instal plug, I bought it used in 2007) My battery is acting funny the past week, still starts, but have a backup just in case for my trip this weeekend.
 
#30 ·
I have not replaced the battery. It still has the original OEM battery from 2003. I figure if it has enough power to start the engine, it's still good. Once the alternator is running, the whole system should see 14 volts or so.

No other electrical problems are indicated when the engine falters. No dash lights, no loss of A/C, radio, etc. Only the horsepower of the engine drops off dramatically. In order to feel good about this truck again, I need to know that the root cause has been found and corrected. Before I start throwing more parts at it in the hopes of fixing the problem by coincidence, I will give some very serious thought to buying a new truck.
 
#33 ·
I have not replaced the battery. It still has the original OEM battery from 2003. I figure if it has enough power to start the engine, it's still good. Once the alternator is running, the whole system should see 14 volts or so.
Not true. At least not in the R/T world. There have been numerous R/Ts in the club that had this issue. Our symptom usually is a rough idle, or no idle at all. Even though the truck will start. It's easy enough to get your battery tested. Autozone, Pep Boys, etc. , they will all do a bettery test for you. These dodge computers are very finnicky when it comes to battery voltage. And, I'm pretty sure your 03 uses the same computer system as the R/Ts, your 5.9 is exactly the same as mine.
 
#34 ·
And some of the load testers at autozone or pep boys will not find the bad batteries, as well!
 
#37 ·
you have two good avenues to troubleshoot at this point. this problem is fixable and your spend on parts would be less than $500 even if you bought every possible replacement part we've discussed.
talking about the replacement truck is a little backwards all things considered. considering the age of your truck, it's more than likely an issue with the O2 sensor or cat.

ohm out the wires going to the pre cat sensor if all is good, buy a new O2 sensor, cut out the cat or replace it, and do some wiring upgrades. you'll probably be good after that
your ECU has a counter on it, it's not going to throw a CEL until you've hit a quota on misfires, or the sensor reads (or doesn't read) outside its limits for a window of time

i'm pretty certain (i know it's true with mine), '03 hemis didn't have an EGR, so no worries there
 
#38 ·
A bad cell in the battery will take the 14.2 Alt out put all day long and keep you running, but barely
 
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