Jexey

The past few days my mustangs been acting strange. First off she's been having trouble idling, jumping from 1 grand to about 400 and back up again for a little while before she levels off, then after some driving doing it again. Second, and the issue that's scaring thehell out of me, is that she chugs. She is running rediculously rich lately and if i'm a gear or two up to keep my exhaust quiet in neighborhoods she'll hump realllll bad. It's almost as if i'm getting a misfire / no combustion in one of my cylinders, but under heavy throttle she feels fine. So it's confusing me pretty bad.

Last night I was driving at about 40 mph in 5th gear and she started to hump bad and the check engine light was fllaasshing.

Now what is going on? Any ideas?

theorgnlimprtkillr

check to see if all of the spark plug wires are connected good. My had been doing it and the 3rd spark plug on the passenger side wasn't connected well

yelw02GT

ive had the same problem, not the idle issue, but if im doing anything under 50 is 5th gear, it bucks like its misfiring or somthing, weird, only started happening after cam instal, i did do new plugs recently tho..weird

Jexey

Yeah I just picked up some new plugs i'm praying that's it -my original thoughts were that it was a Fuel Injector going out but I have after market 45 pounders so I'd hope to hell they wouldn't be going out.

Tylus

could you O2 have gone bad and make the engine go into a failsafe mode (run rich)?

but your best bet is the spark plug needs to be reconnected

Jexey

That's very possible, I have no cats so will MIL eliminators fix that?

SVTBill

fuel clogged somewhere? plugs?

Sap

I've discovered the problem !!!

... "about 40 mph in 5th gear"....

Try it in second gear and see if the car runs better.

Jexey

Haha no no no, I keep it up a gear because my exhaust is rediculously loud at night because people are sleeping etc - with 3.73's I can do that without spiking my fuel pressure through the roof and stalling her

xxkazp3rxx

IAC possibly (or whatever its called, lol)? Could also be a bad fuel filter? Bad 02 sensor.. fuel rail pressure sensor.. you dont have cats, so it's not clogged cats... any trouble codes pull on it?