(I have a Solstice GXP but wanted to get input from the Cobalt community as well.)

My engine suddenly bogged down/lost power on the way to work today. It was very sudden. It immediately started running extremely rough and had virtually no power.

I was close to home so hitched a ride back to grab a code reader and it was showing a misfire overall and misfires on cylinders one and two. Since I was very close to home I limped the car back to the house. (CELs are P0300 (engine misfire), 0301 (cyl 1 misfire), 0302 (cyl 2 misfire).)

Since the car has all new spark plugs and all new ignition coil packs, and it’s been running very well lately, I’m wondering if it might be something else like the high-pressure fuel pump.

I also thought about may be a massive boost leak but on inspection I didn’t see anything loose and I just got done re-clamping everything about a week ago and pressure testing it. I guess it could still be a possibility. I did try my best to visually inspect the inner cooler but that’s a bit hard to see. I didn’t see any bulging and I tried to look at the ends the best I could and didn’t see any issues. Again hard to see with it all installed on the car. I can very easily pressure test the inner cooler and piping as I just did that about a week ago and make sure that’s not it.

As far as the fuel pump, does anybody know what they idle fuel pressure should be? I think mine is currently running around 500 to 600 at idle when I checked it after I limped the car home. I backed up a little bit and went forward and it jumped about 1200.

I figure I can double check for boost leaks, pull the car packs and spark plugs and look around but I don’t know if that will tell me much, and check on the fuel pressure. I guess the checked injectors I’d have to get some kind of injector tester.

Is there a good way to test the fuel pump? Any other parts of the fuel system that could’ve gone bad?

Thanks....any input is appreciated.

 

Start with the simple things. Do a boost leak test and inspect the spark plugs. Then you can swap coil the coils and plugs around and see if the misfire follows.

What spark plugs did you install and what was the gap? The LNF tends to be very picky with its plug selection, I normally recommend only using AC Delco Iridium gapped at 0.030 or 0.032" depending on your tune (big turbo guys go smaller than 0.030").

 

SOLUTION: Turns out it was the ignition coil on cylinder #1 (I logged and saw it was cylinder 1, then swapped the ignition coils as you suggested ECaulk and it followed the coil). I just replaced it a month ago so I'll have to see if it was a one off, or if there something causing issues that are making the ignition coil overwork or something weird.



Thanks all.

 

Are you running OEM coilpacks?

 

I replaced them with Carquest Premium ignition coils as that's all they had available when I was troubleshooting a month ago. I've heard some say OEM are better. I just bought one single AC Delco ignition coil as a backup and it's actually made by Denso Japan (what's in the box).

Any recommendations? Are AC Delco or Denso ok or are GM ones made by someone else?

 

AC Delco is owned by GM and operates as their OEM parts company.

 

Thanks.

 

Coil 2 went out just recently (Carquest brand) so I replace all of them with AC Delco. Will see what happens.

 

Just following back up after several months....no issues after I replaced all the ignition coils with AC Delco. None have failed since then. As I'm learning, only buy AC Delco coils.