5.2L missing when cold. Hesitates. backfires.
#1
07-14-2008, 02:57 PM
5.2L missing when cold. Hesitates. backfires.
96 Dodge Ram 1500 4x4 with 5.2L. I bought it new. Now has 150K miles.
Regardless of outside temp, when I first start the truck, after a couple minutes it gets into this missing mode, where it will die out under load, spit back through the throttle body and run like crap. Then after a couple of minutes it kind of clears up and will run ok until the next time started. Does it every time it is started after setting for say an hour or so. I kind of think I feel a miss while driving down the road, holding the gas pedal at an even speed, but if I mash on the pedal the engine accelerates smoothly. Kind of like it doesn't like trying to maintain a constant speed maybe?
History of the truck repairs -
1. Several years ago I had the plenum gasket problem and replaced the plenum plate with that Hughes Engine aluminum kit. Plenum is still ok. Plus the symptoms were different. I had valve rattle back then and other things.
2. IAC on throttle bodyis new (replaced to see if this was the problem).
3. Fuel pump assembly (whole thing from Dodge) is new.
4. Had a problem with the charcoal canister (charcoal loosened and got into vacuum lines) and so right now the canister is actually a hollow case. I dumped out all the charcoal granuals. Not sure what is up with that thing having all the charcoal come loose like that.
5. I think I replaced the EGR a while back, when the canister problem happened before I realized the charcoal was clogging the vacuum line.
Things I have not done (yet)-
1. Original coil.
2. Plugs are a bit old.
3. Cap and rotor are old, but not original.
4. O2 sensors are original.
5. About everything else regarding engine and sensors are all original.
Any ideas what to try next? No error codes are showing up. Real strange problem in that it kind of clears up after going through this crappy first start sequence.
Thanks for any help with this.
Regardless of outside temp, when I first start the truck, after a couple minutes it gets into this missing mode, where it will die out under load, spit back through the throttle body and run like crap. Then after a couple of minutes it kind of clears up and will run ok until the next time started. Does it every time it is started after setting for say an hour or so. I kind of think I feel a miss while driving down the road, holding the gas pedal at an even speed, but if I mash on the pedal the engine accelerates smoothly. Kind of like it doesn't like trying to maintain a constant speed maybe?
History of the truck repairs -
1. Several years ago I had the plenum gasket problem and replaced the plenum plate with that Hughes Engine aluminum kit. Plenum is still ok. Plus the symptoms were different. I had valve rattle back then and other things.
2. IAC on throttle bodyis new (replaced to see if this was the problem).
3. Fuel pump assembly (whole thing from Dodge) is new.
4. Had a problem with the charcoal canister (charcoal loosened and got into vacuum lines) and so right now the canister is actually a hollow case. I dumped out all the charcoal granuals. Not sure what is up with that thing having all the charcoal come loose like that.
5. I think I replaced the EGR a while back, when the canister problem happened before I realized the charcoal was clogging the vacuum line.
Things I have not done (yet)-
1. Original coil.
2. Plugs are a bit old.
3. Cap and rotor are old, but not original.
4. O2 sensors are original.
5. About everything else regarding engine and sensors are all original.
Any ideas what to try next? No error codes are showing up. Real strange problem in that it kind of clears up after going through this crappy first start sequence.
Thanks for any help with this.
#2
07-16-2008, 09:29 PM
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#3
07-16-2008, 10:11 PM
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