88gta_hiflyer

iTrader: (1)

Hey guys. I've got a weird issue that I need some advice with. I've got an LB9 T-5 combo in my GTA. It runs and drives great under load. However, when I first start the car it idles high for several minutes. Usually 1200-1500 rpm. Once it warms up it will slowly drop down to around 800rpm. Whever I put the clutch in it does the same thing, idles high then slowly comes down. This is not really a problem but lately when I put the clutch (such as when coming to a stop sign) it the rpms will drop off sharply and then go back up before slowly coming to a normal idle speed. For example, I will put the clutch in, the idle speed will be about 1500rpm but it will sharply drop to 1000rpm and come back up, almost like it wants to stall. Sometimes it does this three or four times before coming down to a normal idle speed. Any ideas what might cause this? My first guess would be MAF, ECM, or possibly a clogged EGR valve. Has anyone else had this problem?

88gta_hiflyer

iTrader: (1)

Nobody has ever had this problem or might know what would cause it?

Sandman22

any codes? Have you checked or cleaned your idle air control motor? I had major idling issues with my tpi before i bought a new IAC motor and cleaned out the port it sticks into (very important), I installed one without doing that and it just went right back to running crappy, (but my idle was low not high) after 20 years it gets really gunked up in there. I'd imagine it could go the opposite too though. Also is throttle response normal (as far as you know)? If not it could be possible the TPS is off in voltage (in which case it would need to be adjusted, or idle reset). But its a quick and easy thing you can check at least... I hope that can cross a few things off the list possibly

88gta_hiflyer

iTrader: (1)

No codes at all. A couple of months ago I cleaned the throttle body really well. I also removed and cleaned the iac motor and housing and set the tps voltage. The throttle response is great and the car has no other issues. I have heard that a clogged egr could cause this type of problem but I don't have any experience in that department. Does that sound like a possible cause?

chads89ta

iTrader: (6)

try spraying throttle shaft with carb cleeaner if idle comes up, maybe bad shaft and bushings