86 NA idle problem
 

I did do a search and all the posts ive found werent replied to so heres my problem. I noticed when i left the house today that when i started it up when the idle dropped it went to 500 then bounced to 1000 and kept doing that. I revved it a bit and it cleared up. I drove it to get lunch and noticed it almost died pulling off the hwy. It struggled around 500 to 0 rpm and would occasionally make a rattle metallic noise. I think the noise is related to such a low idle. I know regular engines will rattle and knock if the idle drops under 500. Ive heard of secondary throttle plates causing it.

Re: 86 NA idle problem
 

1. Throttle cable is too tight/wearing out
2. TPS out of position, needs to be readjusted
3. Injectors clogging up
4. Fuel pump or fuel lines

Re: 86 NA idle problem
 

I just got done tearing into it. I just replaced the throttle cable. It's almost as tight as it can go but it doesnt pull on the throttle plate. There's some slack. I have to pull the intake off so I may check TPS and run a pressurized cleaner through the injector rail to clean them when I pull them off. I found when I took the throttle boot off the plates were spotless with minor dirt on them. In the process, I cleaned out the idle valve on the driver side of the intake. It had some carbon buildup inside. I got it to run and idle but it still idled around 500. I turned the screw on the intake and got it up to 750-800 range. It runs great now. It still seems to run a little rough but smooths out off idle. When I cleaned up around the idle valve with brake cleaner I sprayed the intake where the upper meets the center portion (driver side, the hard to get to upside down bolts) and it bogged down. I continued to spray at this joint and it kept bogging as long as I sprayed the gasket. I'm gona get a intake gasket set this week and take it all apart and replace that upper gasket and all the vacuum lines under the intake next weekend. Then i'll re-adjust the idle down. I've kinda got it bandaided for now. It runs normal, rpm drops to about 500 when you let off the gas and doesnt bog too low and it doesnt stall anymore.