2000 Gt problems

[slow00gt]

the car has been missing real bad at idle but if you drive it its fine but sometimes will miss in lower rpms say 1000 2000 but clears up after that and at WOT. Put a scanner on it and the short term readings are showing 1 side of the motor is showing real lean so the car is dumping fuel to that 1 side to compensate for the extreme lean condition. i put a Dragon upper intake plenum and 70mm accufab throttle body on it and since then the miss has started and gotten worse. Not sure if the mods have made something go wacky or the tps is off or if it can even be adjusted. i just know the car ran fine until i added the mods and i cant find the miss or what is causing it. What i have done.

Tried to find a possible vacumm leak (none found)
Changed plugs NGK R
unplugged coils while car was running
unplugged injectors while car was running

I havent been able to pinpoint the miss this way, Any ideas out there?I have a diablo tuner so i can do minor adjusting but cant control idle conditions.

[JohnC]

If it came with those screw in PCV/vacuum line fittings, did you use some thread sealant to make sure it wouldn't leak in some unmetered air?

Did you use a new IAC gasket, TB gasket, EGR and plenum gasket?

Did you TQ all bolts to spec?

Check the TPS voltage, too.

[Keiths2KGT]

Check the TPS voltage, too.

I would start here.

[ReefBlueCoupe]

A bad O2 sensor could cause your lean condition on one side.

[pge27]

A bad O2 sensor could cause your lean condition on one side.

I second that

[bigmike83]

I would start here.

yeah best starting place.
then make sure you have no vacuum leaks.(gaskets, lines, ect.)

also is there a check engine light on?

[slow00gt]

the check engine light stays on. the car has no cats. I was told last night by a guy that figured out what it was doing that if the 02 is reading it should be fine. Also i have the o2 sensors mills turned off on my predator and then i updated the predator and i lost all control of that. I havent found a leak anywhere unless its a lower intake gasket leak. only code it was sending other than the o2 codes for them being off is iac codes but i think those popped up when we unplugged it while the car was running. Also when i changed the plugs it showed a lean condition on the side but not much more different from the other side. I think the lean condition on the plugs is coming from the 100 shot

[2000AtlanticGT]

What about the IAC if that is the code you are getting? Those things are prone to getting dirty and/or going bad.

[floyd4ford]

i just know the car ran fine until i added the mods


You alredy know what the problem is^^^^^^^^^^^^^^^^ Just backtrack what you did when you installed all the stuff..

[bigmike83]

my check engine light is off and i have long tubes and no cats. even with my off road x pipe and factory manifolds just with mil elem. my check engine light stayed off. you might want to look into that. turn the back o2s off and reset the computer and see what that light is on for.
but i do agree with floyd4ford, might be a sensor that was removed and went bad. i've replaced my iac valved twice already.
also try some factory plugs and see if that helps. my ngk tr6 bottle plugs do stumble a little

[JohnC]

If you have a IAC code, replace the IAC and clear the codes with your tuner. Drive it again, let it relearn everything and see if the codes come back.

[slow00gt]

i have cleared the codes a couple times i get the iac code if we unplug it playing with the car. Also the miss didnt happen right away with the mods but it was a day or so after. Im thinking maybe the mass air is going wack becuase the car has never been tuned other than with a predator. maybe with the CAI throttle bodie and plenum it has wacked the mass air into thinking the car is getting way to much air. If it is that i dont understand why it is only affecting one side of the motor. cruising at low rpms and idle is the miss if you WOT it clears missing and seems fine other than the power it had isnt there.I am on a really tight budget and i would like to pinpoint the problem becuase money is really tight around the house these days and i dont want to start pooring parts on it just guessing at what it is.

[2000AtlanticGT]

So when you reset the codes and drive the car, touching nothing, there are no codes? If you have not tried that do and let us know what codes you get if any.

Also, I have heard of people cleaning their IAC and that working at least for a little while. If the IAC is causing the problem, it really needs to be replaced.

[Keiths2KGT]

i've read alot where people install the TB and Plenum and somehow jack up the TPS and have to get a new one.

[slow00gt]

i put the original tune in the car last night cleared the codes and heres what im getting. OBD2 system readiness not complete and o2 circuit on bank 1. Also i had a freind tell me thats a machanic if the tps isnt right it could be dumping fuel into the motor im gonna put it on a scanner later and were gonna look at some voltages for maf etc.

[ReefBlueCoupe]

Is there someone you can borrow an O2 sensor from?

[slow00gt]

im gonna go buy one ad see. The exact code is o2 senor circuit slow response (bank1).Banke 1 is the side that is acting up so i hoping the o2 is not responding fast enough to what the car is doing

[mstrpth]

I SAY...... tell everyone you have cams! thats the easiest thing to do and its FREE!!

[JohnC]

Sounds 100% like a bad O2. Replace it and report back.

[slow00gt]

replaced the o2 car runs great. the short term is a little off but not much on the other bank so im gonna go on and replace the other side. The o2 i pulled out was as white snow.

[Woody]

YAY! :cool:

[Keiths2KGT]

:party:

[LINELOCKSRUS]

:clap: