Misfire Problems

[aldend123]

Hi,

GF's car is misfiring quite bad. Even under light load or at idle. I'm going to take a look at it tomorrow, with the game plan of checking the plugs, the ignition coils, compression test etc. I also need to see the codes its generating. I'll be posting tomorrow with more details.

What I'm looking for right now is common misfire causing problems that might be more common with the 8G Galant (4 cyl) than most cars. If there are any. I'm not familiar with these cars at all.

What compression is considered acceptable, and anyone have a good gap to run the spark plugs at?

[iisaac021]

I had misfires and i changed the plugs and wires and i was good to go

[ADExternal]

i have random misfires (P300) on my 02 2.4 atm and is still trying to figure out wtf is causeing it. Already change the wires and coils, TP, clean the EGR Valve and Intake Valve, triple checked for any vacumn leakes already and clean my injectors every 10k miles. My plugs are fairly new but you never know, so im going to get those change the upcoming weekend. But some of these are ideas you could look into for your problem that may cause the random misfires.

[varroa]

well just pull a couple of plugs and take a look at them. maybe post pictures here.
"fairly new" doesn't mean much if there is a problem with the plugs.

"random misfire" means misfire in all cylinders?

[ADExternal]

thats the thing about it, random misfires can be in one cylinder sometimes or in all cylinder sometimes or just 3/4 etc. Its so vague which is why its a one of the annoying problem to solve. I might check my fuel rail and pump

[ezekiel.glnt]

i would do a compression or even a leak down test to rule out a mechanical prob.

[rowdyprouty]

I had a misfire for some time, tried everything. Replaced coils, valve gasket tube seals(if you have oil in the tubes when you pull plug you should do this(I had oil in 2, just a little) Wires were replaced. Now it was my fault because on my last plug change I cheaped out and PAID for it. I bought good platinum plugs, properly pre gapped( last ones were supposed to be, shame on me for not checking) I forget what I got but they had 2 or 4 electrodes and the price difference was $6 for all 4(cheapies) and $15 all 4 good platinum. Moral of the story, never go cheap! I never will again. Changed them and has been great for months. Check your gap and buy good parts. Good luck.

[Gotti]

Po300 = compression, timing is off, bad fuel.
Pcm reflash if its a cold misfire

[rowdyprouty]

I believe Gap on standard plugs is .044

[2000galantv630]

I recently worked on a 2000 galant with a V6 that had a P0300. I took out the plugs and they were Autolite double platinums that didn't look too good. I replaced them with the cheaper NGK, p/n 7092 or BKR6EGP. It drives great, but yesterday i go a P0302, i erased that code, then today i got a P0306. Has anyone had problems with spark plugs like this? i thought if i used NGK i would be good, but i'm thinking i should have bought the NGK p/n PFR6G-11 which were original equipment, but they were $13 apiece