Bit of a weird idle...

[281CJ]

I know this if for a mach1 but seems I'll get more traffic here than on the Mach1 site.

My mods are in my sig.

When I am rolling out of gear coasting to a light say 45 or 35 range the RPM's jump around as if they are trying to keep the car from stalling, they don't just hang at a specific RPM it's just from 500 to 1400 and bumps up and down never settling till I stop trying to keep itself from stalling.

When I do stop the RPM's hang @ about 1100-1200 then I hear a garble from my exhaust and the RPM's drop to about 875 and the idle is normal.

Any ideas? I'm planning to move back to an 80MM to see if it straightens out if I can't just do a quick tune fix.

 

[01yellercobra]

My first thought would be the usual stuff. When was the last time the MAF was cleaned? What about the IAC? Are you running a custom tune or a canned tune? If it's a canned tune is it for the 90mm MAF? If it's for the 90mm MAF and you go back to the 80mm you'll have to put the stock tune back in.

 

[281CJ]

It's a custom tune, for the 90MM MAF.

I have recently cleaned the MAF and IAC. I have the original 80M MAF calibration so I can just copy/baste that into my tune since I have the PRP. I just have to find a 80MM housing, Mine cracked a few days ago.

 

[01yellercobra]

You can always try datalogging to see if anything pops up. Are you going into coast fuel shut off before this happens?

 

[281CJ]

I'll have to check, at the moment I only have access to Mac. I'm going to try and borrow a PC, but if I can't I'm just going to have a local shop retune it.