Hey folks, I need some help. My 2008 LS recently threw the random misfire code at me. I recently isntalled a cai and ran it for a few days then changed my plugs because the car has.just under 60k and I figured it couldn't hurt. After I changed the plugs I got the cel. So I get home and pull off my cai and replace it with my short ram intake and reset the light. Never came back on. So I did some research and found that a cai should only throw the lean code if any cels at all. So I check my plugs, Bosch platinum +4s, and they are only gapped to 0.020. I regapped them to a 0.035 and reinstalledy cai. So far I havemt had the cel come back on. But what could have caused it in the first place?

 

I would have just taken the plugs out and returned them for a new set by saying they were causing the car to misfire. A plug boot may be seated right on a plug or you may just have had a bad plug.

 

Well I've tried checking the plugs and changing the maf sensor and its still coming on. I think Monday I will be changing the plugs on it and seeing.

 

well first off take those shitty plugs out and put ngk or stock acdelcos in.. Those bosch plugs are junk and cause engines to pop and ect. Reason why is missing under wot and making a lean spot . GET RID OF THEM.!

 

Well I bought and installed a set of ngk platinums. I started it to see if it sounded any better and it did but still had the cel. So I shut it off went in ajd washed my hands then went out to test run it. The cel was off and after a short 10 mile ride it mever came back on so I'm crossing my fingers that thay was the problem. I'll never buy bosch products again though.

 

Ok dont do platniums.... DO iridiums!!

 

Well until I know for sure it was just sh*tty bosch plugs I don't wanna drop $10 a plug for ngk iridiums just yet. Haha. If it fixes it and I don't have any more issues I will be installing a set of iridiums though.

 

Ok so it came back on today. I'm completely baffled by this. Its run just fine for like the past two weeks with no lights. The xar has new ngk plugs abd the only performance thing done is a cold air intakr so far. The needle isn't bpuncing pn the tach but the idle does seem rough. I've replaced the maf sensor. The car.shouldn't need a tune just.from a cai should it? I mean I ran the car for quite a while with a short ram intake with no problems at all so I'm confused right now. Help please.

 

when does the code come up when driving or when sitting idle? if you noticed..

 

At idle.

 

Did you ever get this figured out? I've been fighting the dreaded P0300 code (among others) for over a year now. (06 LT) In the past year alone, I've put a new fuel filter, cleaned (later replaced) throttle body, changed plugs (x2), cleaned and later replaced injectors, and replaced the coil pack. Last winter, she was misfiring to the point that in cold weather she'd stall out, and in both summer and winter, if I sit at idle for a while at a stop light or whatever she'll start shaking, the misfire's that bad. Gonna have a compression test done on her, hopefully this weekend to see if it's the dreaded burned out valves (mech told me this happens alot around 60xxx miles in the balts). Crossing my fingers that it's not, but the mech. is thinking it's either ICM, ECM, a slipped timing belt/chain (whichever one we have lol), or a junk coil pack. Getting sick of throwing money to her and not getting any sort of improvement. :-(

 

u can see if one of ur injectors is clogged a little bit..it haappened to me

 

Try cleaning out the fuel rail,there was another guy quit a while ago that had the same issues and it was full of rusty looking crap.