Hi everybody, I am new to this forum, but have been on here many times you guys are great. I have a 2002 gtp 40th anniversary that I bought for a good deal from a local credit union that was a repo. I drove it off the lot was able to get the car emissions, everything was fine. After driving it for a day my check engine light came on, turns out it was a O2 sensor bank 2. I replaced the O2 sensor, spark plugs (OE style), spark plug wires, cleaned mass air flow sensor, and fuel filter. Car still had check engine light. I reset light now it is a P0304b code cylinder 4 misfire. the car runs a little rough at idle, and gets worse gas mileage than my 2001 by three mpg (yes I love these cars I have two :th_thumb-up
. I checked spark on #4 coil it is weaker than the rest. I replaced with a coil off of my 2001 gtp the spark was still week. I bought a new Ignition control module, still the same. I thought to check the fuel injectors so I replace #5 with #4, still have the problem. I than did compression test it was fine. So because I love the power of these cars I wanted to see how they do performance wise against each other (the 2001 against the 2002). we raced with equal weight the cars are side by side hmmm. Anyways engine is strong at full power. Next I did a leak down test that was less than 10%. I than did a smoke test to see if maybe the intake was leaking it is not. I was watching the misfire on the test computer it goes away at 1600 rpm. I hooked another computer to it, that does 3x and 18x for the cps, I dont really understand it but at idle or up to 1600 rpm the computer graph was going up and down. Above 1600 it stayed in a straight line. I was thinking that maybe something is not right with the crankshaft position sensor, maybe the fin for #4 is bent or something. What do you guys think. The car is in mint condition the carfax shows that the guy that owned it for the first eleven years maintained it very well didn't miss a maintenance interval. the guy that owned it the last two years didn't have maintenance on carfax, but doesn't mean he didn't maintain it. thank you for any help you may be able to give me.
. I checked spark on #4 coil it is weaker than the rest. I replaced with a coil off of my 2001 gtp the spark was still week. I bought a new Ignition control module, still the same. I thought to check the fuel injectors so I replace #5 with #4, still have the problem. I than did compression test it was fine. So because I love the power of these cars I wanted to see how they do performance wise against each other (the 2001 against the 2002). we raced with equal weight the cars are side by side hmmm. Anyways engine is strong at full power. Next I did a leak down test that was less than 10%. I than did a smoke test to see if maybe the intake was leaking it is not. I was watching the misfire on the test computer it goes away at 1600 rpm. I hooked another computer to it, that does 3x and 18x for the cps, I dont really understand it but at idle or up to 1600 rpm the computer graph was going up and down. Above 1600 it stayed in a straight line. I was thinking that maybe something is not right with the crankshaft position sensor, maybe the fin for #4 is bent or something. What do you guys think. The car is in mint condition the carfax shows that the guy that owned it for the first eleven years maintained it very well didn't miss a maintenance interval. the guy that owned it the last two years didn't have maintenance on carfax, but doesn't mean he didn't maintain it. thank you for any help you may be able to give me.
