Questions and Answers

Ford Mustang Misfiring On Stops Q. Hello: I have a 2000 Ford Mustang GT, 4.6 liter, automatic transmission, A/C, P/S, 55,000 miles. Short Story: The car is misfiring. I can make it happen by coming to a stop with hard braking. It then idle rough (missing), a will stay that way for about 5-10 seconds even if I accelerating (albeit sputtering all the way). It sometimes does it on its own while idling; while cruising; while accelerating. Happens maybe once every 5-10 minutes of driving, but no pattern.

Recent background: four weeks ago I got gas. About five minutes later accelerated quickly then had to stop quickly for a red light. The shuddered then quickly stalled. Was hard getting it started. Had to keep my foot on the gas to prevent it from stalling.

Once it started, it sounded like it was missing a few cylinders. Drove that way all the way to Ford dealership. They tested and determine it was two bad coils (#4 and #8 I think). They replaced those coils, all the boots and all the plugs (just in case). They also cleaned something that had carbon buildup having to do with intake. They said it was fixed.

Got the car. Idled smooth for about minutes, then started doing the rough idle and (missing) thing as I described above. I took it back. They kept it for a week and could get no codes to come up and said they were stumped.

I took it to another mechanic. He checked everything and replaced the fuel filter that he said was filthy (original filter). He said it was fixed. Picked up the car. Was fine for about five minutes. Then started doing the same thing.

Past Background: About three months ago, I came out of the house and started the Mustang (cold). It sounded like it was missing a few cylinders and would not idle without my foot on the gas. I turned it off and waited about five minutes. It started up and ran fine until about four weeks ago. Everyone is out of ideas.

Greg

A. If it were me, and I was sure I exhausted every other possibility, I would drop the gas tank and have a look inside. I'm almost willing to bet real money you either fine some garbage or the fuel pump sock is clogged or messed up.