It Just started tonight, I gave my car the work yesterday...
Seafoam, Oil Change, Spark plugs (stock AC Delcos .35 gap) And checked for all and in boost leaks...

The car run good until tonight... I get on it in WOT thru the Baltimore Tunnel And Just gun fire sounds.. The interceptor reads 41 misfires....I;m instantly worried... When driving normal and idle no issues, So i get to my girls house, and Swap in my hold spark plugs...Try to got WOT again Same thing 15 misfires...

I try to reset the ECU and when I start it, it has issue cranking, it eventually cranks over...

Now it doesnt misfire when im partial Throttle, I got it all the way to around 10 psi Partial...Just WOT...I thinking its my HPFP..

WHen i was at the track 3 weeks ago and NLS from 3 to 4 the code for the Fuel pump performance came up..but never again.. I have a HPFP headed down... I'll keep you posted...

Any ideas, suggestions, or comments would be great Thanks!

 

After further Research Could be a injector seal

 

Seal kits are cheap if that makes you feel any better.

 

Yea I don't know where to order them tho

 

did u run all the seafoam out of the system? when i seafoam i cant get on it for awhile till its all out. i get misfire and junk to. just drive nice till its gone then open it out. just wondering if u did

 

Check the spark plug gaps. They should be .030. If they are, you can take them to .028 and see if that helps.

 

Yea its definetly all out, this is a massive misfire... Sounds like gun fire, no power either..Only when WOT tho

I just ordered a injector seal kit, gmparteast

 

Yeah, gmparteast gives pretty quick service. You should get them this week as long as they don't have to backorder them. Sometimes with some things, they do.

 

Yea I hope not, I thought I had everything perfect now this, and my sportline snapped this weekend... so after reading I. Am broke's post seems like the injector seal, right after I seafoamed...

You think I might need a intake mani gasket?

 

I also ordered the 08 ones, those aren't going to be the white ones again...are they?

 

The plugs are at the stock .35..go smaller? I didn't have any issues before

 

I would have got a new one. They are only $6 and it would be a good safety measure on your old one not sealing as its a crush gasket that should only be used once.

 

Maybe I got the wrong measurement. I thought the stock gap was .030 for the LNF. Someone with more knowlege will probably chime in.

I had the exact same issue. I did the same things as you but without the seafoaming. Afterward, torque seemed down and at WOT I got massive backfire.

Soccer helped me with mine. When I bought the plugs, I was guaranteed by the auto parts store that the plugs I were buying were pregapped. I even looked at it with them on their screen to make sure it was the right engine and so forth. I didn't want to gap them because I know on some plugs it's bad to scrape them with metal gapping tool.

Anyway, they were all gapped differently. After I got them all to .030 everything was perfect and has been since. Soccer set his at .028. I don't know if that's due to colder plugs or higher boost levels or what. Hopefully someone who knows about this stuff will chime in.

It wouldn't take long to check the gaps though.

 

Yea, well i swapped in the old ones, and those were fine prior to the seafoaming, Which leads me to beileve its more than that...

 

I have a whole injector unit in my for sale thread. You could put new seals on that and just swap them out.

 

0.035 is stock gap

 

So did you check the gaps? Seriously that's all this sounds like is spark blow out, don't know why you ordered the seal kit.

 

I gapped mine to .32, stopped my misfires

 

I seriously doubt its gap, But i'll try it when i get home, I use my old plugs which worked fine before...Only thing i can think of is the injector seal the symptoms match... I'll do the gap when i get home.. I really dont think its the gap tho

 

Sounds kinda like this...Cobalt ss injector seal - YouTube

not as loud...

 

Lol if it's like the video it is more then likely your gap on your plugs.

 

Startingline, If your right...Imma be pretty mad i order all those parts....We'll find out around 6 when i get off...I wish had tools i'd do it in my jobs parking lot LOL

 

Well if it is your problem then it's a very easy fix then you will have extra parts when needed in the future. If not then try other things. I would just think if you had seals leaking or a gasket leaking you would have a high idle too.but a lot of us go through these problems too and we are all here to help, that's why this form is awesome

 

Yea the idle isnt high, vaccuum is good.. Why the hell would it just start having a spark blow out all a sudden...

yea you guys have been pretty helpful i must say.

 

mine does the same thing but i'm not an ss :/ it misfires at like 5500 rpms in second and third at wot