94 Explorer fuel system problem

[rain_dog_lima]

Last week my 94 Explorer started sputtering and figured it needed new spark plugs or something. When we replaced the plugs there was carbon all over them. Soon after, thick smoke started coming out of the exhaust and the car won't really go anywhere when you press on the gas. We've replaced the air filter and pre- cat converter O2 sensor and neither helped. The computer codes give the following errors: 159, 157, 158 and 186. Three of these four all point to the mass air flow sensor as the problem. I was informed to smell the oil dipstick and I did and it smells like gasoline, not oil. We cleaned the mass air flow sensor and it didn't help. We are stuck between the problem being any of the following: mass airflow sensor, fuel pressure regulator, fuel filter, vacuum leak and/or fuel pump. The car obviously needs an oil change, but we've have held off in case the oil will go right back to having gas leak into it. Any thoughts on what to start with first? The mass air flow sensor could obviously be bad even though it's been cleaned...but would it cause all of the problems I'm having? Thanks for any input!

 

[dogfriend]

I would check the fuel pressure at the delivery rail. It sounds like you are flooding the cylinders with fuel. If the pressure is too high I would check the Fuel Pressure Regulator.

 

[Brock94]

I remember reading about the same problem caused by a bad fuel pressure regulator. It could also be caused by an injector that's stuck open, but check your pressure first. Also, it's not a good idea to run the engine if there's much gas in the oil. That's going to seriously cut down on lubrication.

 

[MrShorty]

When checking the fuel pressure, be sure to pull the vacuum line to the FPr and make sure it doesn't have gas in it. Gas in that vacuum line=bad FPR.