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86 CGT strange idle/power loss after air filter replacement?

Posted: Thu Mar 10, 2016 1:10 am
by mpyatov
Hey guys,

Been a while since I've been around but I'm glad to see there's lots to read about! Anyway I've got an 86 CGT that's currently my daily that's got a few odds and ends that I need to take care of like an exhaust leak, a few interior things and some cosmetic damage but mechanically (except the leak) it's in great shape and I just bought a parts car! So those issues will be resolved soon. However, I decided to replace the air filter after work today because my K&N was wayyy to far gone to clean, ( to the point where it was bowing inside the airbox.) I plugged everything back in and went to fire her up to warm her up before I left, she started, then died. I restarted and the same thing. So I double checked all the wiring, everything was as it should be, everything connected, nothing frayed. So I kicked it on again and held the throttle open manually at about 1k and drove it home with my left foot doing entirely to much work between the clutch and brake.

My initial thought was the IAC valve which is fine, I have a couple more at home, but the problem is that now it's driving terribly. It's so off the power it's painfully. Even with the dirty, bowed out air filter it would still hit the line quick in first, and most certainly in neutral. When I got home and let of the accelerator it started to idle, at less than 500 rpm which is a sad noise. I decided to open the throttle a couple times and it takes almost a solid 3.5 seconds to hit the redline in neutral, which is very unusual. So I suppose my question is, what the hell could be causing it to run so sluggishly after it was running beautifully this morning? Any ideas or feedback would be much appreciated!

Re: 86 CGT strange idle/power loss after air filter replacem

Posted: Thu Mar 10, 2016 1:43 pm
by alxdgr8
Sounds like you've got a vacuum leak. Check to make sure you got the intake boot fully seated, might need an inspection mirror. It's easy to not get it on all the way.

Sent from my Nexus 6P using Tapatalk

Re: 86 CGT strange idle/power loss after air filter replacem

Posted: Thu Mar 10, 2016 11:57 pm
by mpyatov
Turns out I accidentally yanked out the hose that comes out from behind the air box under the intake boot. I guess that's what happens when you do everything in the dark, after 11 hours at work, while reaallllyyy wanting to go home. So I put everything back together and it's running fine. It's definitely considerably smoother than it was but I am still down a little bit on power, but I did just put a Mann filter back in to replace my K&N temporarily so that is probably what that is.