trippinholyman

car runs fine cold then when it hits OT it has a low and high miss/stumble. happens under 2000 and over 5000. most noticeable at wot. thinking icm or a sensor.

survey says?

BlackBird87

iTrader: (6)

Was anything done to the car recently? when was the last tune up? I had a high rpm miss and new plugs gapped to .45 and plug wires fixed it.

trippinholyman

2 yrs / 20,000 miles. I assume it is due for one. I don't believe the 50k or whatever for platinum plugs. I was gonna pull #3 since it was easiest to get but I didn't have a plug socket so I had to go buy one. Now the car is nice and hot so I'm going to wait until tomorrow to look at it. I still think it's ICM or some kind of sensor though. Why would this not occur until it was hot? Unless heat affects the conductivity of the wires or the firing of the plug? And why would it only happen at certain RPMs. Maybe I'm asking it too work too hard when it's heat soaked? Was thinking about getting some washers and doing ICM spacer mod.

trippinholyman

Had body work done recently, new front suspension because I got hit by a woman driver. They didn't touch the ignition. Like I mentioned the last time I had anything ignition done was late winter of 08/09. Had to get a new ignition switch put in the column or w/e it stupidly is located. I bought the car July 08 and had a full tune up done around then, coil, icm, plugs and wires. Not sure on brand, probably oem delco though. My dads work sells Bosch crap too but I don't think they're Bosch plugs since the ceramic is like white/blue like Delco colors.

Maybe O2s? I think he had some Bosch ones put in, or maybe NGK. I forget. I know lots of you guys recommend sticking with stockers. That would explain why it misses when the car warms up (closed loop)

96blackz28

iTrader: (3)

Well from my experience with o2 sensors (on LT1 motors) they will make a car stumble in miss during operating tempature, not on first start up. Secondly, at WOT the o2 readings are ignored so it would run fine at WOT but not partial throttle.

Id lean towards o2's especilly since you have not changed anything.

As for brand, get the OEM ones... I have used NGK, Bosch.. and the Acdelco ones are in now and have been fine for a few years and they are cheaper then Bosch if you know where to buy them

trippinholyman

Yeah and O2s were changed when we did full tune up two years ago also. I'll get my guy to check it with a scanmaster or something see what happens. so the wot is something else probably.

96blackz28

iTrader: (3)

I mis read your post, i see you say WOT it stumbles so def check for burnt wires and all the usuall electrical stuff.
But goodluck man, when a car doesnt run right its the most annoying thing!!

trippinholyman

when you say the usual electrical stuff what do you mean? the most i have ever done on my car is install CAI/muffler/wheel studs