pucksdown

I have an 04 GT, with 92k.

I purchased the car used. Here are the known mods
3.73 gears, cammed, 78mm TB, Off road H pipe, flow masters, tuner.....

Have had the car since April.

The only problem with the car up until now is when I turned the A/C on the idle dropps below 500rpm and would have a hard time idleing.

2 weeks ago I filled up and that's when the problems started. I thought it was bad gas, but the problem is still there with the new tank of gas.

The car seems to idle fine, but has a very noticalbe hesitation/stutter under acceleration. It will smooth out some when the car warms up, but the stutter is still there.

I have cleaned the MAF and have driven with it unplugged, but the problem is still there.

I have cleanded the IAC and TB.

I replaced the fuel filter as well.

One thing I did notice is after I cleaned all these components, the car really ran well, I assume it was because of all the spray in the TB and IAC I used, but once all of that burned off the hesitation/stutter returned.

Any ideas what I should check next?

1998Slow 'Stang

Sounds dumb, but did you reset the computer after cleaning all that stuff?

Also, have you checked your COP boots are not cracked, dry and arcing?

No water in the spark plug wells?

Did you try checking to make sure the plugs are gaped correctly?

Did you try new spark plugs?

How about a new fuel filter since you thought you bought bad gas?

Is the Check ENgine Light on?

If still stock is the air filter dirty, or if aftermarket have you cleaned or replaced it?

Have you made sure you don't have any vacuum leaks after the MAF?

pucksdown

Sounds dumb, but did you reset the computer after cleaning all that stuff? I disconnected the battery while doing each thing for 30 min or longer

Also, have you checked your COP boots are not cracked, dry and arcing? Not yet, but is on my to do list

No water in the spark plug wells? I don't think so

Did you try checking to make sure the plugs are gaped correctly? On my to do list

Did you try new spark plugs? on my to do list

How about a new fuel filter since you thought you bought bad gas? Put new filter on after my last fill up, after what I though might be bad gas.

Is the Check ENgine Light on? no CEL

If still stock is the air filter dirty, or if aftermarket have you cleaned or replaced it? It's and OEM filter, and it's pretty clean

Have you made sure you don't have any vacuum leaks after the MAF? I have checked and didn't notice any leaks.[/COLOR]