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Discussion Starter · #1 ·
I have a 97 Dodge Ram 1500 2wd with the 5.9. The truck has 141000 miles on it. When on the interstate going 60-70 mph I'll be keeping the same speed or going down hill with or without cruise on and in OD it feels like it misses but not all the time. If I give it more throttle it goes clears up. When it started it was only doing it for around 25 miles. Now it will do it for almost a whole trip which is 103 miles one way but not as bad the farther I am along in the trip. I did a tune up of spark plugs, spark plug wires, rotor, and cap a little over 4k miles ago. The truck does have a cold air intake and a throttle body spacer but these have been on for over 12k miles no issue. I think it maybe a TPS or the MAP sensor. I don't have a whole lot of money but need my truck fixed because I need it to help move soon. Please and thanks of the help!
 

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Key dance can be used to check for codes

http://dodgeram.info/Engine-Gas/OBDI/pcm_fault_code.htm

This TSB helps to avoid coil and plug wires from inducing current into neighboring wires when routed too close together and/or parallel to each other; pay attn to the critical coil wire and 5 and 7 wires

http://dodgeram.info/tsb/1998/18-48-98/18-48-98-v8.htm

... A few days ago my 97 at light ish or steady throttle started to feel like it was slightly missing/jerking a bit in higher gears; sure enough that night when observing wires when very dark outside the coil wire was leaking tiny sparks a few inches from coil; then when I moved it a bit, holy schmut leaks/sparks lite up along the wire for about 6" (yes 6" of tiny sparks) but further along the coil wire; (yup, it's toast; but it idled smoother when wire was lifted a bit); anyway, then used some elec tape and hung it an inch ish from heater hose, it no longer has "visible" leaks but truck still has perceptable missing/jerking.
..For now do not need the truck so will pick up a wire set this weekend; for now I "hope" to get away with just changing the coil wire to cure the miss/jerk (plan is for ignition tuneup in spring).
 

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Discussion Starter · #4 · (Edited)
I checked the coil and wires out around a moth ago. I did notice when I was just looking that there was oil around the bottom of the PVC valve and grommet. I pulled the PVC valve out and both ends were covered in oil (enough to cover my fingers) and the the inside of the hose that goes to the intake. I haven't looked inside the intake lately but last time there was a film of clean oil but no pooling in the corners. It is around 1/2 a quart low and its less then 100 miles before I need to do an oil change to it which I do every 3k miles. What would do this to the PVC valve?
 

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there was oil around the bottom of the PVC valve and grommet. I pulled the PVC valve out and both ends were covered in oil (enough to cover my fingers) and the the inside of the hose that goes to the intake.
I haven't looked inside the intake lately but last time there was a film of clean oil but no pooling in the corners.
It is around 1/2 a quart low and its less then 100 miles before I need to do an oil change to it which I do every 3k miles.

What would do this to the PVC valve?
Obviously not oil consumption issue at 1/2 qt per 2900 miles, unless very recent.

... Would check/ensure crankcase breather/hose is clear.
..Maybe PCV valve is toast; or it just recently developed severe blowby on 1 or more cyl/s; or plenum started to leak (keep an eye on plenum, and oil level).
..Or for some other strange reason (severe vac leak??) very very low intake vac is not pulling thru PCV valve/hose properly; would test intake vac.

PCV by nature/task is always dealing with oil/mists, that's why many install "catch cans" to keep oil from entering intake/chambers then cat.
 

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Discussion Starter · #6 ·
If 1 or more cylinders developed severe blow by would that mean and engine overhaul would be needed? For the PVC valve should I get one from the dealer or is there a good after market on? I put an after market on.
 

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If 1 or more cylinders developed severe blow by would that mean and engine overhaul would be needed?

For the PVC valve should I get one from the dealer or is there a good after market on? I put an after market on.
... Unless you have reason to believe cyl/s recently damaged (from overheating, over revving, or driving the pis_ out of it) would not worry about cyls, but would keep a close eye on oil usage till you figure out what's going on!! (to be sure motor and/or plenum is ok; may as well check again for obvious wet oil or pooling oil in plenum, tons of threads/pics/info on this!)
..Easy to check for blowby, but a leaking plenum will give false test result and show up as less than actual blowby (unless blowby is seriously bad).

... Like some other parts, imo dealer PCV valve is fine, but there are likely many other good brands too; but ya, there's a whole lot of effn substandard junk out there nowadays too! (might see what happens over the next few days/week or so; if there are issues or you don't trust the aftermarket PCV valve, when changing it would be a good time to check for blowby regardless of plenum condition)
 

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Discussion Starter · #8 ·
Well I had a little time and me and some techs looked at the PCV valve didn't look too bad but said something isn't right. We tired to look in the intake through the vacuum port the the port was to small to put the tool through and look in there. Ill have to do it Monday when I have more time and run the plenum leak test and the blow by test and if time allows a compression test. I did find out when we hooked up the oscilloscope to the TPS the it wasn't even and is bad. The techs told me to change the oil and make the date and mileage and drive around a thousand miles and see how much I lose. I will check every 100 miles or so.
 

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Does it ping under light load? Oil use will indicate that the plenum gasket may need to be replaced. Run a tank of 91 oct. in it. If the Plenum gasket is not too bad this will mask it and it will run ok. It was said above, Plug wires 5, 7 and the coil wire need to be routed correct. With those miles I bet Plenum gasket if you have never done it.
 
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