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Discussion Starter · #1 ·
Let me start by saying this weekend I cleaned my IMRCs. Got the car back together and when it initially started (battery was unplugged), the car had a low idle and felt like it was missing. I just assumed it was some carb cleaner that had got into the cylinder and maybe fouled a plug temporarily. I revved the motor a few times to clear it out and it started running normally. Idled perfect, A/F looked normal (I have a wideband). I drove it several miles after this change to test things out, didn't experience any problems.

I haven't driven the car in a week since doing the change and started it yesterday and went for a drive. The car started fine, idled normally, A/F looked slightly rich for idle around 15:1 (normally it reads around 20-22:1 due to thermactor pumping air into the system). I didn't really think any of it. Drove to taco hell to get some grub (the whole time the car is running normally). Pull into and notice a part-throttle miss.. it was very slight. When I got off the throttle the idle went low around 600rpms and the motor ran rough. The A/F guage was reading 33:1 - extremely lean! I was puzzled at this point so I gassed it a little, A/F went normal, O2s were switching normally, idle smoothed out again. Then a couple seconds later, same symptoms.

My own feelings are two possible causes:

1) Vacuum leak somewhere which would explain the rough idle and extremely lean A/F at idle. I plan on hooking up a vacuum guage tonight to check idle vacuum.

2) IAC was somehow damaged when I cleaned the upper with TB cleaner. I left the TB, IAC, all that crap attached to the upper when I cleaned it. Didn't really think anything of it. I read a few threads on corral where guys replaced their IAC and corrected the problem. If the IAC was allowing too much air in, it would definitely cause a lean condition and rough idle.

Something else to note, when I go WOT, the A/F ratio dips normally down in the 12 range and stays there, so if it is some kind of vacuum leak, it isnt affecting WOT A/F. The car feels normal WOT also.

Whats everyone else think?

Thanks,
Tony
 

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Discussion Starter · #2 ·
I found my problems. The TB/Intake cleaner I used killed my driver side O2 sensor. Hell, it killed the front and rear O2s. The car didn't light the check engine even though a code was present. I am glad I have an Autotap. It saved me!

I replaced the O2s and the car runs great again!

Tony
 
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