Engine Missing
#1
Engine Missing
Thanks Dan. I'll do a photo shot and get them up, be good to document transformation. The problem is the miss. It is present at idle, more so in gear at a light. Stomp the pedal for take off and the power is there. The miss is most notable on the highway. Under acceleration its ok, it missed under slight decel, like when you start down a grade and just start to back off the pedal. It sets no codes, turns on no lights. It was nearly undetectable when I bought it, but I like to hit all the maintenance on new, used cars and it became very apparent after i changed plugs and wires. I also changed O2 sensor but that was a couple weeks later. Tried some old school shorting of coil packs as suggested by a freind and the spark seems to be weak at intermittent locations across the set. Have subbed ignition modules and coil packs from other engines with no change to results, but have not gone all new yet. I'm lookin for solid proof to validate the purchases first. my 88 sunbird swallowed $700-800 for a similar problem and it was a bad wire all along. I guess I'll leave it at that. Thanks for your interest. Gene
#2
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I would suggest pulling the plugs and inspect them. Look for small differences. Dark plugs will indicate a weak spark. Test the wires and coils. Another possibility is a bad injector.
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What year and badge is your car? You have a miss you can clearly feel, and it doesn't set the check engine light? It should; and give you an error DTC which will tell you which cylinder is misfiring or which ignition item in the circuit is "failing".
If that light isn't ON, the problem has to be interpreted differently. And depending on your year, the ECM/PCM might be averaging fuel/air/ignition if (for instance) the cam or crank sensor isn't getting out a steady signal.Your car will run like crap. In just the case of fuel, you never get a proper LTFT for all of the cells (acceleration, deceleration, idle etc).
A properly functioning ECM/PCM would never let that missing go on, without throwing a code.
If that light isn't ON, the problem has to be interpreted differently. And depending on your year, the ECM/PCM might be averaging fuel/air/ignition if (for instance) the cam or crank sensor isn't getting out a steady signal.Your car will run like crap. In just the case of fuel, you never get a proper LTFT for all of the cells (acceleration, deceleration, idle etc).
A properly functioning ECM/PCM would never let that missing go on, without throwing a code.
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