Idle Stutter at 2nd Stop Sign only

San Diego Scott

Registered User
Whassup? 92 'bird running perfect until last week.

Now, every time I get to the 2nd Stop Sign in the morning the Idle Stutters... every time... only at the 2nd stop Sign! The idle drops down to about 350, thens recovers on its own to 750.
(I know, I know, I should just run that Stop Sign and I won't have to worry about the idle.)

It never happens again all day. Something to do with that first cold start in the morning. Any ideas?
 
It could be your thermostat. I've diagnosed this same problem for a customers '94 GT. Sometimes a thermostat that is getting old or has some mineral buildup on it doesn't open slowly or smoothly anymore. It will actually get a little hotter than it's supposed to then the springs pressure finnaly overcomes the resistance and it pops open fully all at once. This allows cold coolant to flood into the motor from the radiator causing a thermal shock to the coolant temp sensor. The EEC immediately goes to a richer idle mixture in responce, causing a idle hick-up and a few seconds of roughness before things start to stabilize again.

Next time keep a eye on your temperature gauge, if it's diving or fluctuating during this condition that will confirm it. Be sure you're not low on coolant first, before you start it, as that could cause the same thing.

It would be nice if I was able to just know everything but sometimes it's just luck. I had the scanner hooked into the GT and had left the car on the lift from the day before. I started it and waited so the scanner would record the conditions during the hick-up. I had just raised it up because it had an oil leak that I was looking for also. When the idle started fluctuating coolant dripped out of a radiator leak onto my head, so the thermostat just opened. After that I figured it out.

Vernon
 
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you don't need to run that stop sign, Scott. Just take a different route and avoid that particular sign completely. It is obviously giving off some sort of signal that your car does't like. It's probably got one of those tracking devices in it, you know....the ones the government uses to signal the black helicoptors where you are at all times........
 
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