Okay,

To start off my friend has an '01 Mustang with a 3.8l and an auto trans. It has exhaust work, a K&N air filter on a CAI and it had a chip, I think it was from superchips or somethin. Either way his car was running fine, one day he calls me and tells me he must have a coolant leak cause his car overheated down the street from his house. We let the car cool and put water in it, he drove it home and it ran just fine. They called a shop, had it towed there and fixed the leak. Turned out to be a heater hose. He got it back and it stayed cool, but was missing very bad. They took it back to the shop and replaced the plugs, wires, and MAF sensor. The car ran fine for an hour or so, then it started missing again. He found when he unplugged the MAF the car would stop missing and run seemingly okay, save for a weird idle. They took out the chip to see if that helped, but it didn't. I know this is kinda vague, but does anyone have any ideas on what could be causing this?

Thanks,
Tony

 

Why change the MAF, if it was bad, you'd know it as it would do a little more than "miss"?

Problem could be a multitude of problems, could be, but not limited too, any of the following:

Clogged Fuel Filter
Faulty or Failed Fuel Pump
Improperly Gaped Spark Plugs
Faulty Coil Pack or Ignition
Clogged or Faulty Fuel Injectors
Leaking EGR Valve
Faulty EGR Sensor

 

Haha, sounds like a medicine comercial when they list the side affects.

 

That's what I thought. The guy who told him to buy the new MAF didn't seem too bright. When it didn't work though he got his money back and just put the old sensor back on. His dad is suspecting injectors too. I'll link him to this so he can look over the list and go from there.

 

If he needs a coil pack or injectors PM me =]

 

I know this is a little off topic, but after you said that I just thought of the commercials that advertise death as a possible side effect, especially advair which is supposed to cure asthema, but can cause asthema related death lmao.