QuestionQUESTION: Bad hesitation 000-3000 rpm, if you disconnect the knock sensor it will run good. New O2 sensor, plugs,plug wires ohm out, coils ohm out, good spark at idle. Live data shows igition 4-5 when hesitating when not hesitating igition is -30
ANSWER: Hi Todd:
does this have any engine noise when it's accelrating? EG: knocking or sprak knock "ping" if that is the case the knocke sesnor is picking up on the noise and pulling ignition advance timing. That would cause lack of power not really a hesitation. This is an odd one. did you try a new knock sensor in it? If this has no engine noise and no ping then ther is no way the knock sensor should not be picking up on any noise. it could also have bad engine computer if it's registering a knock signal and there isn't any. another reason for it could be EMI If this has aftermarket spark plug wires that are too long for the application and they are draped over the engine and routed to close to the engine wiring harness the plug wires could be inducing this issue. With out seeing it it's really hard to tell you for sure what the issue may be.
Have you tried to drive it with the MAF unplugged? a bad MAF sensor will cause all kinds of issues it's the main engine input for engine load. unplug it and see if that makes a difference. it will still hesitate off the line but see after that if it still there.
good luck :-}
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QUESTION: Yes it has a tick (180,000), I did get a new knock sensor and it seemed ok for a day. Also got a different maf and again I got a half day out of it. Plug wires should be OEM, One other I forgot is the speedometer reads a little high, rpm reads alittle high, coolant sensor new is also reading high these are all reading high at the dash not live data.
Big Thanks for your help. (sons first car)
AnswerIf this has mechanical noise (tick) that is more thne likley where the knock sensor is picking up the siganl and pulling th timing out. if the engine is noisey it's only a matter of time before it starts to self distruct. It's only going to get worse. your only recourse is to kep the senor unplugged and rive it that way and the emission light will be on hopefully you don't have a state emission test becuae with it unplugged it will fail a MIL teat for emissions.
