Erratic Idle

[chash360]

Beyond the afore mentioned checks, yes vacuum leaks can behave this way too, also check that all plugs are firing consistantly, an inductive timing light w/ RPM reading works good for this. Clamp onto each plug wire, and check that the RPM/Flash rate is consistant with the Tach. Try to listen for a solenoid switching when the rev changes, there are 2 of these guys under the intake that are almost identical and easily mixed up when hooking the vacuum lines back up. I would have to check my shop manual for the correct hookup.

[motosparky]

I did install a new O2 sensor to a universal type (1 wire)
Could this be a possible cause?

[f00g00]

If you have a vacuum guage (you can buy one from a parts store for about 20 bucks) hook it up on the hose that goes to the cruise control and see how it reads and let us know if steadily rises with the RPM or is really ratchety and what the reading is.

[motosparky]

I did notice there is no VTV on the dash pot anymore.

Could this cause erratic idle?
I also have a crack on the bottom of the air intake after the MAF sensor.
It does not register as a leak when I do the spray check.
Still messin with this thing : (
Any body wanna buy a nice Supra "CHEAP" ?????????

[chash360]

I would definately try to seal the air leak, I am not familiar with this 'spray test' but if it is leaking, after passage through the MAF Sensor, that is equivalent to a vacuum leak, as far as the computer goes (getting more air flow than is being measured). Do what you can to minimize or eliminate this leak.

Additionally I would suspect the O2 Sensor conversion, if memory serves correct the second wire is just a shield wire, but the operational parameters may not be the same as the stock sensor, and EMI may affect is performance (purpose of the shielding wire). These enignes are heavily reliant upon computer control, everything is manged by computer, including spark timing. You can actually adjust the Cam position sensor out of proper position and the computer will actually try to compensate, and bring the timing back in.

This is also a point you my want to double check. Did you check and adjust your timing with the auto advance turned off? The are 2 connections on the diagnostic plug that you have to short when setting your timing (Cam position sensor). This must be done prior to starting the engine, to prevent the auto compensation. On a typical older car this is the vacuum advance on the distibutor you would plug, but the Supra is all electronic timing, you have to short the proper connection, again I would need to consult my manual, but it should be documented in every manual specific to this engine.

[motosparky]

I did not short sensor when I set timing.
This one is an N/A so there is no CPS but the leak does make since.
It happened when my engine was being re-built so it is a new condition.
Thanks....

[supramacist]

Can someone tell me how to pull codes from my car??? Can I do this myself or does it do it itself ? Do I need a diagnostics computer?

I'm curious because I have never seen my ride throw any thing close to a code other than the bird cage light, lol. We all know what that one is.

Thanks.

[motosparky]

Ya, it real easy.
Start here..

http://www.cygnusx1.net/Supra/Librar...ection=FI&P=23

[supramacist]

Thanks alot. Highly appreciative.