Idle goes up almost to 1k sometimes

ericem · Post by **ericem** » Wed Mar 18, 2009 5:03 am

Hey guys. I noticed after I flushed my coolant system and all. Only a warm start the engine will chug a bit, like between 750-1000rpms it will bounce up and down. Also when I stop after the engine is warmed up, it will sometimes idle at like 500, then sometimes will go up to 1000rpm's when I stop

Also noticed sometimes the fans like to stay on. Could this simply be the ecu coolant sensor? Any other ideas? Thanks!

thehookeup · Post by **thehookeup** » Wed Mar 18, 2009 5:10 am

ECT sensors love to be replaced. does your IAC have coolant lines going to it? did you replace your thermostat when you flushed it. really not much of this makes much sense, but its a place to start

ericem · Post by **ericem** » Wed Mar 18, 2009 5:50 am

Yup replaced a crap load of hoses, thermostat, water pump. All oem.

thehookeup · Post by **thehookeup** » Wed Mar 18, 2009 6:22 am

check to see how much vacuum you have at idle, and then get an idea of what rpm (500-1000) and what your vacuum reading is between those ranges. sounds like a bad IAC

ericem · Post by **ericem** » Wed Mar 18, 2009 6:30 am

Funny you say that. The dealer pulled up some records on the car, and the IAC was replaced a few years ago with a new one. Same with the fuel pump which is loud.

thehookeup · Post by **thehookeup** » Wed Mar 18, 2009 6:46 am

just cause they replaced it, doesnt mean it hasnt gone bad lol. I went through 4 IACs granted not all of them were new, but they all couldnt have had that problem. Id just check that vacuum reading tomorrow, and let us know what it was

ericem · Post by **ericem** » Wed Mar 18, 2009 6:50 am

If it matters. I poured seafoam down the IAC hose.

tahiti350 · Post by **tahiti350** » Wed Mar 18, 2009 7:34 am

Both of my '90's do that same surge thing, most comman after running it long enough to get full warm, then going in a store or something. Up and down for about 10 seconds, then smooths out. I just assumed it was an "off" spot in the fuel/temp maps...

ericem · Post by **ericem** » Thu Mar 19, 2009 1:37 am

Got a temp sensor. Tomorrow its going in

ericem · Post by **ericem** » Thu Mar 19, 2009 9:20 pm

Still the same problem. It didn't go as high of RPM actually and when I start it warm the idle doesn't bounce up and down anymore. Still doesn't seem perfect. What could these coolant lines going to the IAC do? Is it really important. Forgot to check the vacuum. I think it started doing this after pouring seafoam down the IAC maybe.

Still hear the fans run for more then a few minutes when I stop as well. I am thinking it might just be normal behaviour. Not sure about the idle though.

ericem · Post by **ericem** » Fri Mar 20, 2009 3:33 am

Was out tonight. Did it the first few minutes. After a few more restarts it went away. Maybe the ECU was relearning? Car seems pretty good. Interesting how I get alot of turbo lag when I floor it though.

ericem · Post by **ericem** » Sun Mar 22, 2009 5:22 am

I FINALLY make a video and the whole time while making the video, the idle was perfect. Before I made the video kept going up to 1k rpms at idle wtf!!

http://www.youtube.com/watch?v=Gdm4RRdGGnk

anyway enjoy. I did not floor it, just power light and mild throttle.

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Idle goes up almost to 1k sometimes

Idle goes up almost to 1k sometimes