Idle woes on 2004 cobra, the usual issue. lol

[MayoSVT]

Heres the issue-- Car at Normal op . temp will idle around 1100 ish. After coming to a light/stop, the car will hang around 1500, which is getting quite annoying and seems to have a rough idle when it hangs at 1500. The MAF has been cleaned, new TR6 plugs, etc etc.

Ported Sc and inlet, Stock polished TB. EGR delete exhaust are mods currently.



I did notice and had it tested to confirm that the alternator diodes are bad. Could the bad alt. cause a higher than normal idle due to the computer noticing an issue and adjusting the idle itself to keep voltage up?

What kind of IAC test could i do? Is that the "while running unplug IAC and car shoudl die if its good"?


ANy input would be great since I love having a great running torch red cobra

 

[crfrider16]

So first question would be, what is your alternator actuality putting out? That needs to be addressed regardless. Next question is, did this start happening after a specific event? ie changed a part, etc? Or did it just happen on its own. I don't believe our cars have an idle adder based on low voltage, but I could be wrong.

 

[MayoSVT]

It seems like it started on its own really. Changed the plugs when i had a previous vac leak and it began to run rough. It seems to be an intermittent kind of issue. Does it when its cold out, hot out, humid, etc.

I previously DID have a high boost styled intake but changed to the ram air style jlt. Could it really be that with the fan coming on and no heat shield, the turbulent air caused by the fan is tricking the computer? What a freak thing that would be lol.

 

[Bdubbs]

Did you retune after switching intakes? I have idle issue too and trying to get a exact answer on the IAC.

 

[MayoSVT]

I did. it was retuned after. Im starting to lean towards the vac line under the S/c maybe having a crack and dry rotted now. Which, of course, inorder to change it- the s/c has to come off. :/