Idle drops and car shakes at a stop when heated up.

[zachzacharyzak]

Hey integra fans! I have a 1990 acura integra ls. it runs great and has 250000 miles on it! However one thing is driving me crazy that I have been searching for for months and I cant find anything. When i first start my car from a cold start it has a high idle (which is normal ive seen) then after it heats up and gets to med level heat it drops idle and shakes at a stop. Sometimes when i put it in park or neutral it will stop shaking sometimes not. I CAN NOT seem to find the problem:x :evil::evil::evil::evil:. Im starting to think its the coolant temp sensor which is causing the fuel to air mixture ratio to be off. However thats just my thought. Any ideas or info will be greatly appreciated. Also another thing. No matter how long i let my car sit in the morning while heating up for these harsh winter months the temp guage only goes up a little and doesnt go up anymore until i start driving it. This could be normal but ive never seen this before.

 

[enoch723]

has nothing to do with the temp sensor or anything like that. 9 times out of 10 its just the idle controls. Check your slow and fast idle control moduals and if they are fine then just adjust the idle screw on the top of the throttle body

As for the temp not getting high when your sitting, You are right that its normal to get higher when you start moving especially if your driving it hard. But really as long as it just doesnt climb in temp then dont worry about it. Assuming you have the stock engine and not a swap.. the b18's tend to run warm. I think the typical running temp was 215C.. So dont worry about it

 

[djzachtyler]

if this is happening at running temps I'd suspect the o2 sensor is going bad or fouled... it will only relay readings once the car is at operating tems as it doesn't start reading until the exhaust manifold reaches approximately 300 degrees farenheit

this would be far more likely a reason your A/F mixture would be off.

 

[zachzacharyzak]

Thank you all very much. I think ill start with the o2 sensor. Start off cheap since i already adjusted and cleaned all the idle controls back to specification. the o2 sensor would make sense. Newer cars if one goes out you still have 2 or 3 more. It will throw you a code but still run fine. does OBD1 not throw codes? since it eventually leads to the ecm im suprised it doesnt.

 

[Swerve]

Well this could be too simple but I have something like this happen to me when I have the AC or Front/Rear Defroster on and I just turn it off. Could be the O2 sensor too.

 

[zachzacharyzak]

I wish it was that simple haha