QuestionQUESTION: Thank you in advance for the help.
My truck has 220K miles. The truck now runs very rough at 1500 rpm. Tries to die and has upon take-off. Changed the fuel filter and pvc valve. Seems like it runs better after it has run for awhile. There is a hesitation in the acceleration. And at speed, just off load, the engine pulses, so much so that I have heard the u-joints clack.
Thinking it is a fuel supply problem. But I have had a coil on the distributor go bad and the truck ran bad like this then. So I really am at a loss.
Fuel pump and relay switch?
O2 sensor?
Throttle body gasket?
ANSWER: Sounds like you have a bad distributor cap. Lots of these are starting to go bad. Moisture gets in the cap and corrodes the metallic tabs. It doesn't sound like a fuel issue to me, only because if it was it would do it all the time not just at 1500 rpm. also you stated that when it gets hot it runs better, meaning to me the cap is drying out. fuel issues usually happen when the truck gets hot. Change the car and rotor assembly, should be good after that
Feel free to ask anything again
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QUESTION: Thank you for your help, though I am still experiencing the same or almost the same problem.
I have now replaced the fuel filter, PVC valve, distributor complete with new cap and rotor. I decided to replace the distributor when I saw how much it had rusted.
I have checked the plugs and wires, both with visual inspection looks good.
I sprayed the TBI with more than half a can of carb cleaner.
The truck is stock with the exception of the MSD ignition and coil. I believe the spark plug wires are also of a performance grade. All of that is probably five years old now.
Thank you again for your willingness to help those less fortunate
ANSWER: Have you changed the spark control module under the cap? also check the wiring going to the cap module
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QUESTION: Would that come with a new distributor? Also called a stator coil? Yes sir, I have replaced the entire distributor assembly.
Thinking about replacing the wires next. But I am waiting on the 8.5 performance wires.
AnswerI was talking to a fellow mechanic on this issue today. He asked if you have had any engine work done. It sounds to him that maybe a valve spring let go, but I am still at a loss. I will keep trying to help you and talk to more techs to see if they have any ideas
Jimmy
