Car idles around 1000 rpm when started and drops to about 750 as it warms up.
at this point I havent touched throttle. Will idle just fine.
When I raise rpm and let off quickly, it drops to about 500 rpm then surges to about 1200, then drops to about 300 and surges to 1500 then down to about nothing and dies.
When I drive the car, It holds around 1500 rpm until I slow to about 3 mph, then does the surging described about.
Each surge gets a little bit bigger than the last. And it only surges a few times before it dies.

It does this in park. In drive well it just idles faster no surge and i do not need to push on the gas . Once i slow down and idle then bam it surges like crazy. And the tach is shaking like crazy too.

any suggestions

thanks

 

clean out the IAC (idle air control) carbon can build up there and "slow" it down so it has trouble getting your idle under control.

 

its not that I put a new one in. Once I start my car it revs to 1500 then slowly drops back too normal idle then a few seconds later the tach starts shaking then its like I am pushing on the pedal and it surges all the way to 5000 rpm then back down to 2000 then back to say 4000. Just surges anywhere it wants to. So I just have to turn off the key.

 

might be something ignition related if has the motor has to warm up to do this, check the whole system workin ur way from the ignition source to the plugs if possible.....just an idea

 

Did you clean the passage for it when you put the new one in?

 

scan it...sounds like a maf problem or possibly you didn't do something right on the IAC install

 

Just a note, since bubba didn't list his region. If you're in the baton rouge area il'l scan a 93-95 for free.

 

I can scan it myself and things seems alright. Is there anything I should look for on my datamaster file that could be causing this? The afgs or maf is fluctuating when the surge is happening, i noticed the lterm counts for the right side is 140, the left is 128. And this is in open loop so the o2 are not be used. Tps stays at 0% 0.65. Iac counts are fluctuating all over the place......

thanks for the help so far

 

Couldn't this be opti related? My car would surge at idle from 1k to 2-3k. Replaced the opti, and it was fine. Of course, optis are $$$. Want to make sure thats the issue, I suppose.

As a sidenote, my honda did the same thing. I removed the IAC valve and cleaned it(honda dealer told me this was impossible). Fixed the problem.

 

It sounds to me like he didn't clean the IAC passage when he had the IAC motor out.

 

yep....thats what it sounds like....

 

alright yah the iac is all cleaned out perfect, but I was looking at another website and they said if the tach is twitching at idle then that is a sign of the icm. The tach needle twitches then I know right away it is going to start revving up on its own. So I wiggled the icm connector and it started to stumble and rev like it was doing before so it must be that. So i went and fixed the grounds to it and closed the prongs in the connector and even checked if I had proper power to the prongs and ground so forth and put it back in. Still does it and if I wiggle the plug no change now. So it must still be something else. And I just replaced the opti in january. It takes until it fully warms up to do this. Then even if it cools off a bit it will still do it, unless you let it sit for quite a while.

 

okay I found that when it is surging I go and unplug the tps and the surging stops. But the idle stays at like 1500. Now is it thetps that is causing the surging? I would make sense though as i need to warm up the motor then the second I touch the throttle the surging starts. But there is no codes and on datamaster the tps shows 0.65v and does change when the throttle is depressed.

My question is can this tps sensor go bad even if no code is set and appears to be working?

 

Do you have a datamaster log file? if you do email it to Mdenz3@hotmail.com and i'll look at it for you to see if i cna find anything.

 

alright sent datamaster file