Aim having an idle issue when I first start the car the rpm’s will jump from 1500 to 1800rpm. After the engine warms up the car goes to normal 800rpm and stay but when I rev the engine doesn’t matter to what rpm and hold the rpm’s still to a certain rpm, the rpm’s will jump up and back down to the rpm aim trying to stay in and back up again and back down to the rpm’s aim currently holding. Let me know guys I cant figure it out I checked the TPS and its in specs what aim thinking is could be is the wax rod thing but not sure and also I don’t know how to check it. If you have any ideas let me know thanks guys?

 

I have a similar or possibly same issue as yourself. The Factory Service Manual (FSM) refers to the problem (if I understand yours correctly) as "idle hunting." I have not been able to ID the problem yet, but knowledgible FD owner's have suggested I check the following:

- Idle speed control - tried it, disconnected it and ran w/o out, no change
- Accelerated Warm Up (AWS) - have not checked yet
- General check for vacuum leaks - spray carb cleaner in engine bay and see if it affects idle
- Monitor injector duty (using PFC Commander) and see if injector duty is dropping to zero when rpm's drop off - implying that ECU (or PFC) is doing fuel cut as if car thinks I am decelerating

I'm still a newb at troubleshooting, so I have asked for experienced help from a local member. When we determine the fix, I plan to post.

 

Adjust the TPS.

 

Thanks but I did it already. Thanks technomentor I will try those sugestions and see what happens.

 

Yes it sounds like we have the same problem Idle hunting. Keep me updated if you find out on how to fix this problem. Thanks

 

bump

 

do you have an APEXi PowerFC? sounds like your deceleration fuel cut is set too close to your idle speed.

it could also be your AWS

 

NO I dont have a APEXi PowerFC and about the AWS not sure on what that part is.

 

AWS = Solenoid valve, accelerated warmup system (download manual). Atteached to extension manifold (UIM) but underneath and towards firewall side.

IACV = Idle Air Control Valve (Idle Speed Control) is attached to extension manifold towards firewall side. You're idle could possible be the same but most likely it won't stay on and will just keep turning off. with it disconected, touch the gas and it should stumble and die or skyrocket to redline if you have too much idle set. I tested mine when it buzzed like crazy and my car wouldn't hold idle. Driving without it, is like riding a mechanical bull. I just ordered one and they retail for over $400.

 

Thanks for letting me know what AWS.

As far as for the IACV my car doesn’t dye out. When I start the car from a cold start the Idle starts hunting around until it warms up but when you rev to a certain RPM and hold at that RPM the car starts to hunt around again until you release the gas pedal and let it go back to idle RPM but if you do it again and rev and hold it will start all over again and hunt around until you release to idle.

 

Idle hunting problem solved. Mine was related to the accelerated warm-up system (AWS). Pulled the wire in the harness and problem went away. Chuck also worked on smoothing out my idle. No more lumpy/bumpy idle

Note: I run an Apexi Power FC