Idle rises out of nowhere??

[dalatinromeo]

Okay this has been an ongoing problem for my car since I purchased back in 05. Well at times alot in the summer my idle will be normal at 750-800 RPMs then all of a sudden my car idle will spike anywhere from 1500 to 2000 RPMs. It doesn't go back and forth it just raises to a set number and stay there. If I am stopped I get out and lower the idle by pushing it back.

I don't know whats causing this as it does this out of nowhere. Its not like a everyweek thing. Like it will happen today, then in two days, then a week later then another two months it will do it. Kinda of weird but I would like to stop getting out my car to bring down the idle every once in a while.

Any help or suggestions would be appreciatedm

 

[lazyazzdaddy]

when you say you have to get out of the car to bring the idle back down what do you mean? like you have to play with the idle screw or you've got to pull out the throatle cable? just wondering because my car used to do the same thing but a little more often and was kinda predictable. "like when i would drive it hard it would usually do that same type of thing". was a vac problem for me.

 

[pj91gsx]

I think he means he pushes back the throttle. My throttle would stick at 3 to 4 thousand sometimes. I sprayed pb blaster on it and worked with it and it fix it.

 

[lazyazzdaddy]

thats what i thought he was talking about too.. he could just spray it with some lube or just replace the cable and be done with it.

 

[dalatinromeo]

Thanks will try out and let ya know.

 

[1gDSM4g63]

Most likely a vacuum leak, adjustment on your BISS, broken tps or isc sensor.

 

[dalatinromeo]

I dont think it can be the biss screw, because MOST of the time it idles perfectly at 750. It doesn't surge or anything just feels like the thorttle body cable gets stuck.

If the lube doesn't work I will look at TPS and ISC sensor. Will report back later on today.

 

[95tzlgst]

you should make sure that you have the nut on the back of the biss screw

 

[dalatinromeo]

Will check that too.

 

[ROOKIE1]

you should make sure that you have the nut on the back of the biss screw

The biss doesn't have a nut . The SAS does .
2G BISS Adjustment

 

[95tzlgst]

sorry rookie mistake. but the sas would back out and cause my idle to mess up until I bought some nut from the dealer and after that I didn't have an idle problem.

 

[dalatinromeo]

Well the pb blaster on the throttle body cable didn't work. Guess I'll check for vaccuum leaks and the biss screw.

 

[pj91gsx]

Does the throttle more easy? I would reccomend doing a boost leak test because it will send air threw all of the vacuum lines and turbo/intercooler system. Spray soapy water on the vacuum lines and intercooler and turbo system.

 

[cjridert1]

Do you have anything to log what your ECU is doing? The idle switch on the back of the TB is often a pain for high idles; mine did this for a while and I could usually correct it by 'blipping' the throttle quick to bring the idle down. Log your idle switch and see if it is on or not (alternatively, open the hood when it is idling fast and see if closing the TB plate brings your idle down - loosen your cable if so). Have you done boost leaks? The TB shaft seals are prone to getting aged and letting your car pull in some extra air for idle. Good luck!!

 

[dalatinromeo]

I got a pocketlogger but I gotta download the software again my batteries died adn I got to load it back on.

But the when it does go up sometimes I do "blip" it a bit, and sometimes it does go down. And yes when the idle rises out of nowhere I get out and push on the throttle body cable to push down the idle. And it goes back to 750-800 rpms.

Yeah I'm about to do a boost leak test this week. I couldn't check the car this weekend, I was too busy. Will be checking this week. Update you guys in a few.

 

[pj91gsx]

I got a pocketlogger but I gotta download the software again my batteries died adn I got to load it back on.

But the when it does go up sometimes I do "blip" it a bit, and sometimes it does go down. And yes when the idle rises out of nowhere I get out and push on the throttle body cable to push down the idle. And it goes back to 750-800 rpms.

If that is the case then your Throttle cable is clearly sticking. maybe its not the part that you see, I would clean out the whole Throttle body. The TB will build up oil in it over time.

Yeah I'm about to do a boost leak test this week. I couldn't check the car this weekend, I was too busy. Will be checking this week. Update you guys in a few.

That is a good idea to do. spray soapy water on everything.

 

[dalatinromeo]

Well this weekend I stopped by my friend's house to work on his car and my car. He had the same problem with the idle rising. So I told him I'm finally trying to figure out the problem he let me know he had fixed his already. He told me he changed the throttle body cable and the problem was fixed.

So ordering my throttle body cable this week. Just like some of you guys were mentioning.