2002 GTP cylinder 4 misfire

**BRUTEL 1** · 12-28-2011

I just bought tonight a 2002 GTP, really clean car but high miles (150,000) all highway. It is misfiring on cylinder #4 Problem stays on #4 when swapping plugs, wires, coil. No intermix in oil or coolant. Car will drive anywhere, just has a miss. It is blowing oil out of the dip stick tube when driving. Guy i bought it from has it has a piston out of it. I don't this so, but what do you guys think? What tests should i do next?

Thanks for any help
Rich

**brandonl2000** · 12-28-2011

you tried switching the fuel injector on cylinder 4 to another one and see if it moves??

and for the oil, perhaps PCV valve?

**Explicit_Spade** · 12-28-2011

That's not really what's considered "high miles", insurance averages are around 14k per year.

If it's not in the Plug, Wire, or Coil, its either an injector or Ignition control module. Possibly in a rare case the fuel rail could have something plugging that cylinder.

Oil blowing out the tube is a pcv issue.

The only way to know if it's a piston is to do a borescope or tear the top end off.

**BRUTEL 1** · 12-28-2011

do these cars have problems with pistons?

**98GPGT2D** · 12-28-2011

You can do a compression test, or better yet, a cylinder leak down test. The leak down test would be a good one if you have access to an air compressor.

Jay

**Explicit_Spade** · 12-28-2011

Not unless you fail at modding. Is your car bone stock?

**BRUTEL 1** · 12-28-2011

The guy said the oil blowing out the tube started with the misfire.

Could a rocker stud have pulled out of the head. I heard of that

**BRUTEL 1** · 12-28-2011

100% stock

**Explicit_Spade** · 12-28-2011

If a rocker stud came out, the rocker would be ticking.

Do you have a check engine light on? If so what are the codes it's on for?

**BRUTEL 1** · 12-28-2011

Originally Posted by Explicit_Spade

If a rocker stud came out, the rocker would be ticking.

Do you have a check engine light on? If so what are the codes it's on for?

p0304

**BRUTEL 1** · 12-28-2011

could it be a problem with a valve in the head? Seems like the crankcase is being pressurized blowing the oil out. I think its all related

**Explicit_Spade** · 12-28-2011

OBD-II Trouble Code: P0304 Cylinder 4 Four Misfire Detected

**98GPGT2D** · 12-28-2011

Do a cylinder leak down test like I stated above, to help narrow down the possibilities. It will tell you if you have a piston issue. I'm thinking you have a hole in the piston or the ring lands are busted up (know issue) allowing combustion gas's and pressures to enter the crank case and pressurize the crankcase. A cylinder leak down test, or even a boroscope will tell a better tale.

Jay