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Hesitation / Bucking

if you are blowing out spark, you may be building up carbon/fuel deposits on the plug itself.. thereby reducing the gap naturally?

SWAG, at the most, on my part... I am tired and just got home, so who knows.. I can't really think of ANY reason it would stop.
 
Striker2, if you had a NA car, I'd suggest unplugging the MAF to see if the MAF was the problem. Your symptoms sound similar to what I was experiencing in my Zetec and a new MAF fixed the problem.

Unfortunately, I don't know if unplugging the MAF in an FI application is a good idea. Maybe the turbo gurus can chime in.
 
its a brand spanking new lightning MAF. i dont think its the problem (and no its not a good idea to unplug it in a turbo car).

i did replace my cam and crank sensors as the resistance in both were above what 2 known good ones tested at. it seems to have helped quite a bit. im going to replace my plug wires soon and see if that helps any as well (hopefully it will). if not then im back to the wiring harness or IAC.
 
i know thats why i said wiring harness first. if the harness is cracked, which i know my pre98 is starting to, then it could find power/ground (whichever one the PCM controls) through another cracked wire. this would open the IAC and could cause hesitation/bucking problems.

the IAC comes into play if its getting stuck open slightly. however that SHOULD cause problems all the time. i need a new one anyways as i have a surging idle and its 247K miles old. so i need to replace it.

im gonna start with the plug wires though as replacing what controls the injector and spark timing seemed to help a lot.
 
Well, I would think 35 thousandths is a bit on the tight side but if it works then I'd use it. The other thing to keep in mind is that the plug wires, plugs and plug gap are all interdependent.
Meaning if you piece together different ones you will get different results in terms of the amount of gap you can run. That is because the performance of the spark is based on the resistance of the whole setup from coil-wires-plugs to grounds.
High resistance wires may require a tighter plug gap possibly.
 
Well noted. Also, I will note that I have since expanded the gap to 40 thousandths and still am able to maintain spark up to 14psi.
 
i have THE SAME PROBLEM on my car. it started out as the throttle position sensor wire was almost cut through on the wiring harness because i had an SAFC hooked up. i redid the wires, and took out the SAFC. the car used to stutter allt eh way through the power band and now it only stutters if i have the MSD installed. i'm guessing the added voltage from the SAFC is causing the coil to spike (stock coil 170k on it) if i disconnect the MSD it goes away, but it has much less bottom end power without the MSD on it. could i put my 3L coilpack on or will that not comply with the 2.5L wiring harness?


oh yeah and i should add that i run the plug gap with the MSD at 52 thousandths. i ran it at 40 without but i havent changed it lately. i'm going to try new plugs again. my car right now also runs worse after it rains, which makes me think something makes a voltage change somewhere, like a wire is exposed and gets wet or somethign of that sort. any ideas folks?
 
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well in my case (not sure who your saying this to) my car runs extremely rich. with that and the stock timing curve, it's fine. it did run lean before i fixed the TPS wire but it's fine now on the wideband :) detonation=bad
 
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