Idle acting all funky

[dutch]

Hey guys, just drove the cobra for the hell of it tonight and the idle went all funky on me. It did this once before last summer, but has been driving fine all of last week.

Basicly, I noticed it driving around letting off the throttle, it kept moving by itself and didn't engine break much. None of that sweet overrun burble and popping like it normally does.

Then when I came back home idle was bouncing between 500-1000 rpms, was less obvious with the lights off or when the fan kicked in, but still there. Almost die, and jump back to 1000rpm constantly.


I haven't touched anything since the last few times I drove it, and wanted to ask around before I mucked anything up.

Car is pretty much stock with a K&N and accufab single blade (po installed everything). I cleaned the MAF when it did this the first time before winter, also cleaned the TB blade etc, but it was already squeeky clean to start with. I'm thinking about cleaning out the IAC, or could the TPS be dieing on me? It's just weird because it acts fine 99% of the time, but I couldnt get it to idle or engine break normally tonight.

edit: forgot to add, no check engine light and vacuum is a steady 22+ inhg as always.

 

[cobra-k]

Perhaps the alt is taking a poo? They will do things like that if they are on the way out. Do you have a fuel pressure gauge? Did you notice it drop in pressure at all? Could be clogged fuel filter or dying pumps. I'd also check voltage on that alt and see what its doing. Hope this helps.

 

[GoGreen04]

Alternator, FRPS, or fuel filter is my guess.

 

[dutch]

running a stock 8psi eaton can damage the FRPS? The car still pulls like a freighttrain when I give it some, just idle and decel are funky.

 

[dutch]

Cleaned IAC (was a little dirty), reinstalled and the idle started surging right from cold, even died twice because it let the revs drop too low. Then I disconnected the battery to reset the ECU and it seems to be ok now. Idled ok and drive ok.. Now I don't know what happened?

 

[GoGreen04]

Maybe the ECU just needed a reset. Sometimes they idle funky coming out if winter storage. May have also been bad fuel going through the system. When my FRPS went bad it was showing same symptoms that's why I said it

 

[dutch]

It idled and drove fine coming out of storage.. started doing this out of nowhere.

I guess we'll see what happens next few drives.. thanks