Random Misfire? [Archive] - GrandAmGT.com Forum


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12-28-2012, 10:13 PM
My car has been acting strange lately. I would start it up and it would run like crap for the first minute or two and the check engine light would flash a couple times and then go out. I'd drive the car and it would sputter for a bit and then run fine, just the first few minutes.

I took it to get the code checked out and they said it was a random misfire (think code 302 or 303?) any ideas what this could be so I'm not throwing parts at it? Thanks in advance!

12-28-2012, 10:32 PM
Check your plugs and wires first

12-29-2012, 06:03 PM
Along with plugs and wires, clean up the connection at the coils, I had 1 rust! Wires, then plugs would be where I started also

12-29-2012, 08:45 PM
Ok ill check those tomorrow...didn't know if a cool was going?

I do have a set of new msd plug wires I had for my old Camaro, I wonder if I can make these work? Hmmm

12-29-2012, 08:51 PM
Wait untill It's dark out, get a spray bottle of windex, and spray all around ignition wiring. Plug wires, coils, etc. If you have a problem you'll see a nice show, and be able to determine what's causing it, unless its something internal.

12-30-2012, 03:02 AM
if its blinking it means multiple cyl misfire...im pretty sure thats what the manual say...could be wrong thought so you may get a nice show with the windex trick...ill have to try that sometime . good idea....

12-30-2012, 06:05 AM
Plugs and wires are probably going bad. Coils are a possibility, have them tested. Autozone can actually test them, that is...if they actually know how. The Autozone I used to work at actually had the tester for ignition coils, very handy.

Also, don't count out any of the fuel injectors. They perfectly emulate a misfire and throw misfire codes. I've seen it happen with many LA1 and L36 powered GM cars.

04-16-2013, 09:47 PM

any resolution to this? I have the exact same issue.. seems to be misfiring first 500FT then smooth sailing

04-16-2013, 10:16 PM
I Dont know what the problem is in your case but when i had my LA1 i had exactly the same symptoms and It ended up being a cracked head along with the head gaskets, hope yours isnt that bad, it could be alot other stuf

04-16-2013, 10:32 PM
i sure hope it's not a cracked head, just bought it 9 months ago and only put on 4000 miles so far.

plug # 4 looks to be normal looking with a tad bit of white. but nothing major.. i'm going to remove #1 as it got the p0301 code once,

I'm hoping its just a ICM or coil pack.. or plugs.

04-16-2013, 10:41 PM
Yeah like i said it could be alot of other stuff i hope is something easy and cheap to fix.

04-17-2013, 08:14 PM
i too have had this issue for a while now. it only misses on cold starts for about min or less, and when its under a heavy load

things i have tried to replace


still missing, i dont get it. i pray its not a head, good lord.

04-17-2013, 09:35 PM
Now that you mentioned "injectors" i just remembered i have a set of injectors that came with my 3500 engine and some 02 sensors. I might put them up for sale for a very low price just to get rid of them. Or maybe sell them in a G6 forum? considering these parts wont work on a LA1?