TBI acting up

Dunno what's up (thinking vacuum leak maybe), but when I'm at a light all of a sudden the idle kicks ujp and the SES light goes on and I can feel the car surge. at this condition the car with 'idle' at 25-30 mph. then a few min later it'll stop and the revs drop back....

any ideas?

Sounds to me like idle air motor. Could also be the throttle plate sensor. Would also check all the various plugs and grounds. The car is, after all, 18 or 19 years old.

Bill

Are there any codes? It could be a number of things. Start with the codes.

Bill actually the car is over 20 years old now. Built in Nov '90!!!!

As time permits (work is CRAZY right now), I'll get to checking everything.

Fred, the funny part is the SES light doesn't stay on and I tried to use the paper clip method and no codes showed up ( they clear themselves....)

Could also be an intermitent connection to the O2 sensor. When the ECM can"t see the O2, it goes back into open loop. Could account for the high idle. My original 91 did this in the winter if it took more than a couple of minutes to light off the O2. Would trigger the SES light until the O2 started communicating.

Bill

thanks Bill, I'll check that out first. It's weird as it'll go on and off several times in a 15 minute drive.

You might have a cracked vacuum line. Try a couple drops of diswashing liquid in a pint of water...squirt it on any place there is a common vacuum. If the water is sucked up, you have found a leak. I say common vacuum because an intake manifold leak will probably not cause the variation in idle speed. Check your throttle body bolts too. They can come loose.

You could try disconnecting your EGR system, It could be another possible malfunction. Pull the line off of the EGR valve, and plug it.

The Haynes manual says the water temp sender could be another fault.

When did you last change your PCV valve?

Fred Kiehl wrote:

You might have a cracked vacuum line. Try a couple drops of diswashing liquid in a pint of water...squirt it on any place there is a common vacuum. If the water is sucked up, you have found a leak. I say common vacuum because an intake manifold leak will probably not cause the variation in idle speed. Check your throttle body bolts too. They can come loose.

You could try disconnecting your EGR system, It could be another possible malfunction. Pull the line off of the EGR valve, and plug it.

The Haynes manual says the water temp sender could be another fault.

When did you last change your PCV valve?

What PCV valve? It's been missing since I bought the car.

Didn't affect it on my 3300 mi+ romp to wagonfest so I doubt that's it!

Will try and figure out the other stuff later this week when I have a couple days off.

It's the TPS. My '91 did the exact same thing. If you pull the code it'll be something like "TPS voltage high" or out of range.

thanks tyler, I'll start with that one. still no time to look at anything.....holidaze and work BAH!!!