68CSTANG

Hey guys, I am having a small issue with my 2000 GT. It has zero mods and 95,000 miles.

Here is what it is doing:
-It has a miss in the lower RPMs "sometimes." It doesnt seem to be consistent with coolant temp, outside temp, etc.

-If I have the AC on, it sometimes wants to surge at idle.

The plugs and fuel filter have 10k miles on them. I also had to replace the intake with one with an aluminum crossover. This was also 10k miles ago.

It isnt throwing any codes.

What do you guys think? Im a bit stumped and trying to get this pig ready for a 9 hour trip.

Thanks

Repzard

Almost sounds like IAC or a failing COP to me.I had a COP failing and it would sometimes miss at idle then it failed one day missing in all RPMs.I found the failing COP by removing fuel injector wires one at a time listening to idle changes.
I know when I put my A\C on in my 99 GT the idle surges.
But thats do to low refrigerant but I dont use the A\C but it sux when you need that defroster .

GL hope you fix issue.


Repzard

98redstang

+1 def sounds like an iac problem to me.

68CSTANG

But the IAC wouldnt cause a buck/miss at low RPMs would it? Or does it still function after idle?

Maybe I have two issues?

Also worth noting to point towards the IAC; sometimes when I put the car in gear, the RPMs will drop, and then jump up to 2000 or so. Really annoying.

Thanks

98redstang

clean the iac and than go from there. Also clean your maf. These are the most common causes for you problems

sn95_331_GT_ yellow

+1 for this

68CSTANG

I cleaned the IAC and MAF and it still has the same symptoms. Tried to pull codes again and it still isnt throwing any.

Any more ideas?

Thanks guys

98redstang

hmmm do you still have an egr? i know sometimes these cause random problems if they get stuck.

Andy13186

I had the same symptoms and it was a leaking heater hose dripping on one of my coil over plugs

trailor

yea clean out the EGR port holes too. the IAC technically can't be cleaned (read up on some of cliffyk's articles). if it has problems, it should be replaced. that being said, i have sprayed some carb cleaner in mine before and cleaned it out a bit and noticed that the weird noise it makes when its going bad went away (still sticks when shifting, especially when the AC is on..). either way, it could still be part of the problem.

how bad is the surge at idle when using AC? describe those symptoms a little more in detail please