rogersj

hey guys my ss/tc is missing bad mods in sig. somtimes it happens at 4 k and others at 6k. runs and drives normal at lower rpms very smooth but when i get into it i cant get to the top of third. second gear seems to be fine untill 6k. pulled codes with trifecta and this is what came up.
P0451
P0689
P0300
P0301
car has new plugs ngk irdiums gaped to .32 pulled plugs today to check gap and the gap was fine alog with a nice brown color on the plugs. where should i start next?

Nabes07SS

I know p0300 is random misfire and p0301 means its #1 cylinder. With out looking them up I don't know what the other codes are off the top of my head. Would be nice to know before any advice is given. But if it were me i'd check fuel delivery and ignition. If you can, record data when you are driving it and get it to act up. Then look back at fuel trims, spark, advance ect ect. Something will tell a story and lead you in the right direction.

serega12

iTrader: (1)

^^^Leakdown/compression test.


Could be caused by a cracked piston/ring. That's what caused mine. Do a compression/leakdown test. It will tell you almost for sure...

If you are still under warranty and let the dealer mess with it, they'll replace your ignition coils and do a bunch of other unrelated stuff first... (that's what they did for me anyways)

It could cause the other codes too (at least the exhaust one, you'd be leaking pressure through your crank case and by the turbo) if your piston is cracked.

Just make sure they machine the heads when they do it, I believe they forgot to do it on mine, and it's back in the shop now. Had them do a leakdown test, it failed (cylinder 1 lost 15%, while 2, 3, and 4 lost only 3%)

rogersj

ill do a compression test tomorrow and ill let you guys know the results. also the car seems to be fine when i switch to stock tune. maybe a little miss at the top of the rpm but nothing like when the tune is on.

tomj77

iTrader: (2)

If pistons are good, try stock plugs. Acdelcos

ECaulk

iTrader: (6)

Also move the coil pack from cylinder 1 to cylinder 4 see if the misfire moves

rogersj

Just done compression test and got 165-170 on #1 got 160-165 on the rest

rogersj

Just pulled maf its dirty. Could this cause my problems. Also what can i use to clean it? Carb cleaner or brake clean. Theres no maf cleaner in my town

09CobaltSS1

First and foremost, before you go crazy with any tests check your battery voltage and alternator output through the rpm range. It may sound odd but trust me, throwing a p0689 code along with random misfire codes puts up an immediate flag to check the battery.

rogersj

14.4 volts when driving never droped below 13.8. Do you think its possible i got that code because of a loose ground terminal on my battery. i randomly lost all power. Terminal clamp was broken. Still not sure on the missfire

09CobaltSS1

Absolutely! A bad battery, chassis or body ground will cause horrible misfire (both ignition and injector). Repair the ground and make sure there are no other corroded or weak grounds, leave the battery disconnected for 5 minutes or so, take the car for a ride and see if the problem is still there. How is the battery voltage static btw (car off/ignition off)?

rogersj

Thanks for the help. I fixed the battery 2 weeks ago and was wondering if it was an older history code. A week later still have bad miss fires at higher rpm. Car off battery votage 12.8

09CobaltSS1

Ahh, yes then that's most likely an old code assuming there has been no voltage issues since then. You didn't mention that one in your op though..

Could have been an easy fix for you if that was the case..

rogersj

Found maf cleaner. Going to clean the maf and try that

rogersj

Cleaned maf and car runs alot better up top but just b4 its time to shift i can feel her bucking a bit

yamaha288

I bet it injectors I have pretty much narrowed down the same symptoms to injectors just dont want to spend the money on them.

ECaulk

iTrader: (6)

I'm assuming you're running 93? And did you try swapping coil pack from 1 to 4?

rogersj

Theres only crappy 91 octane here in newfoundland
yes i swaped coil 1and 4 and now i cant get a code for misfire. I can get through the rpm range but at 5500 rpm theres a miss. Also got acdelco plugs on order for monday morning