QuestionQUESTION: i have a 02 chev silverado with 5.3. i keep getting codes po131, po151, and po157. i have replaced fuel pump, fuel filter, o2 sensors, both catalytic converters, spark plugs. if i have the codes erased then it runs ok until they pop up again. it happens at about half to 3/4 throttle, or just driving around slow in the mountains. i cant figure it out. any help would be great.
ANSWER: hi quick question.... how does it run when codes pop back up.
Any difference in performance?
Please let me know
Pawl
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QUESTION: when the light is on it runs fine if im just barely in the throttle but mid range its really sluggish and will sometimes start to misfire. if i give it full throttle then it runs better but not quite as good as it has and can. once the light is off (codes erased) it runs ok but not normal. it runs like it would if the engine was cold, where there isnt much power at first then its like you hit a power band once you get to higher rpms. i kinda wonder if there isnt enough back pressure? i have high flow cats and flowmasters' race car mufflers that are only 6 inches long? i dont know.
AnswerHi
The aftermarket exhaust COULD be your problem. I would first, however check ALL welds and joints, etc.... for any leaks.
All these codes are for Lean exhaust.
I would also check ANY condition that could cause a true lean exhaust (lean = too much air or not enough fuel)
No air filter. Plugged fuel filter, faulty fuel pump, vacuum leak, exhaust leak, etc.....
I Hope this helps
Just advice from experience.
Good Luck
Pawl
