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Discussion Starter #1
I have a 95 5.2 v8 dakota runs like a top for about 20 minutes then it starts to slightly cutout then starts to backfire pop and crack until it cools down then can drive it for 20 min more before it does it again any ideas?
 

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I have a 95 5.2 v8 dakota runs like a top for about 20 minutes then it starts to slightly cutout then starts to backfire pop and crack until it cools down then can drive it for 20 min more before it does it again any ideas?
This is sometimes a symptom of a bad throttle position sensor, random cutting out, stalling, and backfiring.
Does it have normal power? Does it tend to run hot? You might check for a plugged converter if this is the case.
 

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Thank you for suggestions i have replaced tps iac map temp sensor plugs wires cap and rotor cutting off cat tomorrow and straight piping it will let you know Thanks.
 

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I have a 95 5.2 v8 dakota runs like a top for about 20 minutes then it starts to slightly cutout then starts to backfire pop and crack until it cools down then can drive it for 20 min more before it does it again any ideas?

Given what you mentioned, the problem is obviously fuel related, right. So the key here is at 20 min timeframe something happens. Backfiring, hiccups and the like -- irregular fuel/timing condition. A little background info ... Upon warmup, the engine's fuel/timing management system goes passive, or what is referred to as open loop. Once optimum temp is reached, the ECU/PCM will engage the closed loop and begin to map fuel and timing according to response via Oxygen sensors, among others. To me, I'd wager most my money one of your O2 sensors is failing or has failed. There ought to be stored codes, but not always; given the year and it being an OBDI electronic system, smart tool diagnostics are limited. You can check O2 sensors with a multimeter. The FSM or deep googling ought to provide you with the range your sensors should operate. These are low ohm systems, too. I'd be inclined to start there simply due to timeframe, temp and the fact you haven't mentioned investigating those sensors.



Good luck.
 

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Welder,using a scanner find out what codes are in memory. write them down and keep them. Erase PCM codes and repeat previous step. See what returns. There is plenty to speculate but you will surely run out of money before you run out of parts to change. Autozone will read the codes for free. you need to decide which direction to follow,Fuel or Electronics.Pay a reputable shop for an hour of diagnostic time. Measurement of fuel pressure is a must. Before you cut off the CAT, removing one of the O2 sensors or simply loosening up the exhaust piping will get you the same diagnostic results,which is do Have more than one inch of back-pressure. Re-racking electrical connectors and cleaning grounds is a simple/easy way to eliminate electrical. Placing a vacuum gage on the intake manifold and interpret the readings will tell you how the engine is breathing.or if there are timing issues related to mechanical problems. A Haynes manual is a economic way to understand what it is your dealing with. Hope this helps! Get back to us with some results and we will give you guidance thanks, Mongoman
 

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You can unplug the 02 and the pcm will run the motor in a default setting rather than removing everything to see if it improves.
 

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Thank you for suggestions i have replaced tps iac map temp sensor plugs wires cap and rotor cutting off cat tomorrow and straight piping it will let you know Thanks.
I hope you're planning to replace that catalyst. Defeating emission controls is illegal and will not improve performance. If you remove the catalyst you will have a permanent check engine light, and the engine will never run closed loop again. This is not how you solve problems.
 

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I hope you're planning to replace that catalyst. Defeating emission controls is illegal and will not improve performance. If you remove the catalyst you will have a permanent check engine light, and the engine will never run closed loop again. This is not how you solve problems.
Correction.

The O2 sensor used for closed loop is BEFORE the catalyst and is not affected by the presence or absence thereof.

The O2 sensor DOWNSTREAM is used to verify the catalytic converter is working; I don't think it's ever used for feedback otherwise.

But yes, I'd replace it. But then, I was raised in the 60's and believe in doing my bit for the enviroment.

RwP
 

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Discussion Starter #10
Well new cat and muffler no change in popping and backfiring checked all connections unplugged o2 sensor no change same with pcm no codes show up put fuel pressure gage on it and ran it till it started running like crap and had steady 39psi at all times it does have an old reman pcm. STUMPED
 
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