Need help figuring out my idle problem still??

85begalttype

just a v6
Joined
Oct 22, 2008
85 t-type pretty much stock(afpr, 86 ecm, tt chip)

readings at idle, warmed up, iac around 20-30, tps is at .46, maf at 5, o2 is around .700, blm is around 129. fuel pressure line off is around 43#

from cold start to warmed up, engine idles alright, some little stumbling. When i put it in drive then park again, or when turned off and then on again, it misses and stumbles bad. my o2 reading goes down to around .10 and sometimes zero. so i guess it starts to run lean. then i give it some gas and the o2 goes around normal again for a bit.

found no vacuum leaks, i unplugged the maf and it almost stalling. unplugged the cam sensor while running and it dies right out.

maf, o2 and iac are all new. seems like the only things left are either the cam or crank sensor. cant even see the crank sensor from overhead. cam sensor is that round cap above the water pump?

car runs great when driving around, just doesnt idle without stumbling and missing
 
85 t-type pretty much stock(afpr, 86 ecm, tt chip)

readings at idle, warmed up, iac around 20-30, tps is at .46, maf at 5, o2 is around .700, blm is around 129. fuel pressure line off is around 43#

from cold start to warmed up, engine idles alright, some little stumbling. When i put it in drive then park again, or when turned off and then on again, it misses and stumbles bad. my o2 reading goes down to around .10 and sometimes zero. so i guess it starts to run lean. then i give it some gas and the o2 goes around normal again for a bit.

found no vacuum leaks, i unplugged the maf and it almost stalling. unplugged the cam sensor while running and it dies right out.

maf, o2 and iac are all new. seems like the only things left are either the cam or crank sensor. cant even see the crank sensor from overhead. cam sensor is that round cap above the water pump?

car runs great when driving around, just doesnt idle without stumbling and missing

mine has been doing this for 2 years now and it is driving me nuts. when i start it up cold it idles smooth but a little sputtering out pipes then when warm the idle is rough and the o2's range from 100 to 780 but when i hit my alkytest button it smooths out and the o2's are 800 and idle is smooth and then when the alky gets used up it runs rough and the 02's drop. i changed everything and it still does it. did this just come out of the blue because mine did. used to run perfect then one day this start intermittantly then now its constant
 
Had the problem since i have had the car, was told it was the iac. It was the iac, among everything else.
 
IAC counts should be as close to single digits as you can get at idle. Maybe remove it and clean out the iac boss in the TB. Generally the 02's bounce around at idle so you cant really take those as a reference except at WOT where they meant to be used for tuning.
 
IAC counts should be as close to single digits as you can get at idle. Maybe remove it and clean out the iac boss in the TB. Generally the 02's bounce around at idle so you cant really take those as a reference except at WOT where they meant to be used for tuning.

turbo tweak chip has 02's locked in at idle and mine used to do it but it now doesnt and i tried everything as well as new chips from eric
 
I have the same problem, I found my IAC loose, removed, cleaned and reinstalled and the car idled like a champ for about a day. I also adjusted the TPS while I was at it, I will check the TPS volts tomorrow to rule the TPS out. If the TPS is good I will throw a new IAC at it and see what it does. I'm not to worried about it because the car runs like a champ otherwise. Just spent 4 hours on the road with it today...Boston and back and it ran great.


(um....Knock on wood):wink:
 
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