misfire on number 5 piston

[sabercat]

i have a 99 grrand prix gtp the service engine light is on pulled codes it said number 5 piston misfire i go to get on it and it is very sluggish like the power isnt there

[dsmuts]

Check plug and wire then if those are fine move fuel injector to another cylinder. If that doesn't work move coil.

[smoke14]

I've got the same problem. Installed a ZZP 2.5" cat'd dp. and now cylinder 5 is missing when it revs past 3k. and idles rough. There's only 155xxx kms on it and the only other mods are E3 spark plugs and a cai

[dsmuts]

E3 plugs could be your problem ^^

[REDCRAPGP]

Change the plugs to something either iridium or copper than report

[Dee23]

Yeah, those E3 spark plugs are funny, they were meant for certain applications....I think its 3 or 4 ground electrodes on those and I think all it does is block the spark(opposed to them saying you'll get a much better spark)

Especially if your modding, you really dont want E3 spark plugs. But at the end of the day, 3800 motors just dont like E3 spark plugs

[smoke14]

I will try to change the plugs by the weekend, also forgot to add that I have a P0420 code as well as the misfire. Do I Maby need my computer tuned?

[dsmuts]

You maybe have a clogged cat.

[BillBoost37]

Likely the cat ZZP has in there isn't up to snuff with what your pcm expects to see.

[matt5112]

Yeah, those E3 spark plugs are funny, they were meant for certain applications....I think its 3 or 4 ground electrodes on those and I think all it does is block the spark(opposed to them saying you'll get a much better spark)

Especially if your modding, you really dont want E3 spark plugs. But at the end of the day, 3800 motors just dont like E3 spark plugs

Meant for the garbage.

[BillBoost37]

Matt...Dee's post or E3's?

[smoke14]

The cat is CanAmMex and not Magnaflow like ZZP advertised. So what would be the cheapest way to fix this? Would this also cause the misfires, or is that a separate problem? And yes I'm gonna pull those E3's out, don't like anything I've read about them.

[Dee23]

, wus going on here? Did i say something wrong or did somebody take something I said the wrong way?

IDK, I honestly just dont trust those E3s, but its the drivers preference....but at the end of the day its really the motor that decides what it likes best

[smoke14]

I swaped out those E3's for NGK's and no more misfires. I still get the P0420 code and after reading a few other threads on here it sounds like I need a tune PCM. however the car still drives fine and I'm not getting horrible mpg's unlike what I've read in other threads.

[dsmuts]

told you so about the plugs lol. Your cat is probably clogged

[smoke14]

It's a cat'd dp from zzp that's 2 weeks old.

[dsmuts]

high flow cat will do that.

[chevyy1212]

OP I got a misfire from frying a plug running fuel injector cleaner. That's my story

[smoke14]

Ok, so do I need a PCM tune from Overkill, ZZP, ect. or can I just leave it as is?

[Fivefingerdeathpunch]

If you want you can try getting the o2 farther away from the rear of the cat or make it not stick down in the exhaust stream as much so it doesnt see all of the exhaust but enough to still say its working correctly.

Its a little trick that sometimes works.


Or have some tune your car or buy a pcm.