Strange high RPM's
Thread Starter
Joined: May 2009
Posts: 4,915
Likes: 40
From: Far West
Car: 1986 Camaro Z28 IROC-Z
Engine: 350 Tuned Port Injection, for now.
Transmission: 700R4
Axle/Gears: Posi - 3.23
Strange high RPM's
Earlier today I did a burnout from a stop sign. When I got home, I put it in park, and I had an unusual high RPM's (1,100 rpm). I turned off the IROC and fired her back up and it was at the normal 600 rpm's. I have no troublecodes either. What can be causing this? I searched up and down in my repair manuals for a solution but I couldnt find anything. Any advice guys?
http://www.youtube.com/watch?v=qOBQTlFUoag

http://www.youtube.com/watch?v=qOBQTlFUoag
Joined: Dec 2004
Posts: 16,740
Likes: 994
From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: Strange high RPM's
almost like the park neutral switch was stuck. weird only you !!! lol
Thread Starter
Joined: May 2009
Posts: 4,915
Likes: 40
From: Far West
Car: 1986 Camaro Z28 IROC-Z
Engine: 350 Tuned Port Injection, for now.
Transmission: 700R4
Axle/Gears: Posi - 3.23
Re: Strange high RPM's
Sup my friend. Come to think of it. About 2 years ago, I went to turn on the IROC and I had absolutely no crank nor click. Almost like as if the battery was stone cold dead. But after a few turns of the key, it fired up quick. Not sure if that is relavent to the neutral switch.
Junior Member
Joined: Jun 2007
Posts: 16
Likes: 0
From: San Antonio, TX
Car: 1985 Trans Am
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: BW 9 Bolt 3:27
Re: Strange high RPM's
Sup my friend. Come to think of it. About 2 years ago, I went to turn on the IROC and I had absolutely no crank nor click. Almost like as if the battery was stone cold dead. But after a few turns of the key, it fired up quick. Not sure if that is relavent to the neutral switch.
Thread Starter
Joined: May 2009
Posts: 4,915
Likes: 40
From: Far West
Car: 1986 Camaro Z28 IROC-Z
Engine: 350 Tuned Port Injection, for now.
Transmission: 700R4
Axle/Gears: Posi - 3.23
Re: Strange high RPM's
I had a problem just like this, the car didn't react at all when I would try cranking it. My dad and I had found that if we wiggled the shifter a little bit when it was still in park, there was a certain "spot" that it would crank in. Eventually, it stopped cranking in park completely, so I had to crank in neutral. Once I replaced the neutral safety switch, it totally fixed my issue!
Joined: Dec 2004
Posts: 16,740
Likes: 994
From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: Strange high RPM's
wonder if the ect is messed up or the throttle shaft is worn.
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Thread Starter
Joined: May 2009
Posts: 4,915
Likes: 40
From: Far West
Car: 1986 Camaro Z28 IROC-Z
Engine: 350 Tuned Port Injection, for now.
Transmission: 700R4
Axle/Gears: Posi - 3.23
Re: Strange high RPM's
BRIAN!!! Sup brother. Whats the throttle shaft? I actually thought about checking the voltage of the TPS when the idle is good. But then when it acts up, check it agian. Perhaps I got a spike or a bad spot on the TPS.
Joined: Dec 2004
Posts: 16,740
Likes: 994
From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: Strange high RPM's
sup andrew !, nice avatar
The throttle shaft on the throttle body. The stock throttle body wears into the aluminum and over the years can cause a vacuum leak. You can feel the end play moving the shaft back and forth from the front of the car to the back in direction. It should be almost none. sometime you can feel it in the 1/4 throttle position. carb and choke cleaner can also help find a leak spaying in around the throttle linkage side of the throttle body shaft.
The throttle shaft on the throttle body. The stock throttle body wears into the aluminum and over the years can cause a vacuum leak. You can feel the end play moving the shaft back and forth from the front of the car to the back in direction. It should be almost none. sometime you can feel it in the 1/4 throttle position. carb and choke cleaner can also help find a leak spaying in around the throttle linkage side of the throttle body shaft. Thread Starter
Joined: May 2009
Posts: 4,915
Likes: 40
From: Far West
Car: 1986 Camaro Z28 IROC-Z
Engine: 350 Tuned Port Injection, for now.
Transmission: 700R4
Axle/Gears: Posi - 3.23
Re: Strange high RPM's
Thanks. I did the photoshop myself. Ok. I'll check into that tomorrow (play on the tb).
Thread Starter
Joined: May 2009
Posts: 4,915
Likes: 40
From: Far West
Car: 1986 Camaro Z28 IROC-Z
Engine: 350 Tuned Port Injection, for now.
Transmission: 700R4
Axle/Gears: Posi - 3.23
Re: Strange high RPM's
Joined: Dec 2004
Posts: 16,740
Likes: 994
From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: Strange high RPM's
It's like a mini iroc, how do you squeeze in there lol
Thread Starter
Joined: May 2009
Posts: 4,915
Likes: 40
From: Far West
Car: 1986 Camaro Z28 IROC-Z
Engine: 350 Tuned Port Injection, for now.
Transmission: 700R4
Axle/Gears: Posi - 3.23
Re: Strange high RPM's
Suck in the stomach and squeeze in. Thats the easy part. I have to honk the horn with my nose. hahahaha
Supreme Member



Joined: Nov 2001
Posts: 2,266
Likes: 37
From: Canada,Ont
Car: 1987 TransAm Ttop
Engine: 2005 LQ4
Transmission: Ls1 T56
Axle/Gears: 3:54
Re: Strange high RPM's
my old throttle body did this after hammering on it.a few issues with that stock piece i had was a weak return spring not letting the throttle blades return back and I could pull back on the gas pedal and drop the idle,plus the throttle shaft and blades were gummed up from years of carbon build.if your motor is built up then i suggest just getting a new throttle body and upgrade now..or have the stock one rebuilt and polish it up to flow some more.
Thread Starter
Joined: May 2009
Posts: 4,915
Likes: 40
From: Far West
Car: 1986 Camaro Z28 IROC-Z
Engine: 350 Tuned Port Injection, for now.
Transmission: 700R4
Axle/Gears: Posi - 3.23
Re: Strange high RPM's
So it may be a mechanical failure? hhmmm.... New Throttlebody..... Sounds like I hear a 52mm at my doorstep.. hahaha
Supreme Member



Joined: Nov 2001
Posts: 2,266
Likes: 37
From: Canada,Ont
Car: 1987 TransAm Ttop
Engine: 2005 LQ4
Transmission: Ls1 T56
Axle/Gears: 3:54
Re: Strange high RPM's
well its a new throttle body or first try a $10 can of throttle body cleaner first.Take it off..remove the iac and give the throttle body a good bath.let it dry and put it back on and hope it prolongs its life.i got away with that for awhile.
Thread Starter
Joined: May 2009
Posts: 4,915
Likes: 40
From: Far West
Car: 1986 Camaro Z28 IROC-Z
Engine: 350 Tuned Port Injection, for now.
Transmission: 700R4
Axle/Gears: Posi - 3.23
Re: Strange high RPM's
I already sprayed the tb last month when I put on a new "IROC-Z" TB upper plate. Problem was there before and after.
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