FIXED: bent spark plug electrode

Problem:
Misfire P0304 on cylinder # 4 after motor stock motor swap

facts of the car:
Did a stock motor swap because of a rod knock
Owner did not want to do the T-belt, W/P, cam sensor etc... because motor had low miles aprox. 50,000 on it and is trying to sve money as usual and will pay for that maintance at the dealer recommended milage.
Before rod knock problem the car melted coil pak #3. The car owner had a friend repalce the melted coil pak with a brand new one and continued to drive the car for a couple hundred miles with a rough idle and occassional stalling when coming to a stop and then the rod knock developed.

The friend of the car owner contacts me to replace the motor. I replace the motor and now there is a Misfire P0304 on cyl.#4. I swapped all of the coil paks around and the problem stays on cyl.#4. So I am assuming all the coil paks are in good working condition because the problem never went to another cylinder.

Could the melted coil pak have damaged the ecu? The problem started with cyl.#3 but is now on cyl.#4.
Should I try a new or good known ecu? Could it be the cam sensor?

Thanks for your time.

 

Have you checked the freeze data? What's it saying?

Have you tried swapping injectors?

Have you inspected the spark plug(s)? How about swapping them?

I'd start with the easier stuff first, but would not rule out a faulty ECU or a bad connection.





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New NGK's and I did swap over the original intake manifold complete with sensors and injectors using a new intake manifold gasket. I am not using the one that came with the replacement motor.

Took out the ecu to look for any thing burnt inside. Looked fine and re-installed, started car same problem P0304 and now a P0300 random misfire and P0302 cyl.#2 misfire. Clear the codes out start it back up and the P0304 always comes back. I've cleared them then restart and the other two codes happen intermittently.
I also opened up the plastic cover on the harness to check for shorted or burnt wires on on the #3 cyl. coil pak connector and it looks fine.

I got an Auto X-Ray EZ-Scan 5000 scanner. I'll see what it says. I got a head ache currently from this crap.

 

Which NGK plugs did you use? If they're not the PZFR6F-11 plugs, you need to change them again.

Have you checked the fuel pressure?

I'd try changing the injectors around too, to see if the misfire jumps to a different cylinder.


That's weird that there's no other visible damage as a result of the coil pack melting.

 

Problem solved, it was a bent spark plug electrode. Gap totally closed. The person who knows me and the car owner helped me with the engine removal and intake manifold swap and he was the one who installed the plugs. My guess is he dropped them down the tube instead of using the plug socket. Checked all the plugs and the rest were fine. Regapped #4 and all is great. Never over look the obvisous or the simplest things, and a this was a first for me.

Thanks for your time.

 

Ah-ha! Well, at least it was easy to fix.