[Keithj3]

What’s up fellas , I’m stumped on this one and need a few ideas . Car is a 2016 2ss , lt4 short block , lt1 heads , cammed , lt4 blower , upgraded fuel system and on e85 . Car ran great all season and thru the winter ( yes I daily this missile haha ) anyway one day after the gym I stopped in a drive thru to get some food , they couldn’t hear me so I shut the car off , when I restarted it I had what seemed to be a misfire and the ses lamp was flashing steadily. I limped it into the parking lot and had it towed to a reputable speed shop . After days of testing they found both banks opposite fuel trims with bank 1 stft -16 and bank 2 stft +20 , and misfiring all on bank 1 only . I’ve had new plugs installed , (new to me ignition coils off a known good car ) tried new injectors oem from local dealer , I’ve had the blower removed several times to have wiring checked , check grounds at back of heads on both sides also added a braided strap ground for insurance sixth gen’s are know. For bad ground issues . I’m stumped on this one guys 2 speed shops now and im about to pull my hair out . Any help is appreciated!

[Megahurtz]

check the exhaust all the way from the manifold gaskets down to the header rear flange. Could also have a bad O2.

But also keep in mind, if a cylinder is misfiring, the O2's will read rich and try to pull fuel. That could be why you see -16 on one bank. That side likely has a misfire. You might have a broken valve spring or bent pushrod. You need to pull the valve covers off and verify things mechanically as well.

[Keithj3]

Originally Posted by Megahurtz

check the exhaust all the way from the manifold gaskets down to the header rear flange. Could also have a bad O2.

But also keep in mind, if a cylinder is misfiring, the O2's will read rich and try to pull fuel. That could be why you see -16 on one bank. That side likely has a misfire. You might have a broken valve spring or bent pushrod. You need to pull the valve covers off and verify things mechanically as well.

Thanks brother, changed both o2’s. And checked all the wiring VERY well nothing!!! Even check compression for for the hell of everything good there. New wires, plugs, still nothing. No broken valve springs and pushrod are straight. This thing is weird.

[Zracer]

Check the header tubes with a temp gun to see if you see one that's not as hot as the others when running . If you can narrow it down to which cylinder its skipping on this well help. Then swap coils from that cylinder to another. Rule one thing out at a time. You might could do a leak down too .

[Keithj3]

Ok thanks for the reply brother. I’ve changed the coils, and no change. But will do the temp on cylinder check later. I’ll get back in few again any ideas are greatly appreciated.

[Keithj3]

Originally Posted by Zracer

Check the header tubes with a temp gun to see if you see one that's not as hot as the others when running . If you can narrow it down to which cylinder its skipping on this well help. Then swap coils from that cylinder to another. Rule one thing out at a time. You might could do a leak down too .

So I checked using the heat gun and it appears that the whole driver side bank is doing this. I’m willing to pay ANYBODY who can figure this problem out!!!!!

[ctrlz]

Rich and lean at the same time... this is an interesting problem.
From what I read this is usually an oscillation problem. Bad O2 sensor, but you already checked that.
Check the MAF.

When you got the "misfire" at restart, were there any loud bangs that might have blown open a vacuum leak somewhere? I think this is less likely.

Also, some ideas here:
https://ls1tech.com/forums/lt1-lt4-m...-bank-2-a.html

[rcoe]

At the end of last winter I had an issue that was taking me in circles similar to yours.

I ended up draining the fuel tank and refilling with fresh 93 and have not had a problem since, best I can figure is I got a bad batch of E85.

Might be worth a try.

[Megahurtz]

Check the main coil pack connector plug on the driver side.

[Zracer]

Like Megahurtz suggested check the coil harness connection on that side. If it's good start checking all your grounds on the engine harness. I've seen a loose ground cause problems like this many times.

[Keithj3]

Originally Posted by ctrlz

Rich and lean at the same time... this is an interesting problem.
From what I read this is usually an oscillation problem. Bad O2 sensor, but you already checked that.
Check the MAF.

When you got the "misfire" at restart, were there any loud bangs that might have blown open a vacuum leak somewhere? I think this is less likely.

Also, some ideas here:
https://ls1tech.com/forums/lt1-lt4-m...-bank-2-a.html

No loud bangs or anything. And the killer is it’s not setting any codes!!! Just the flashing engine light( random miss fire). It’s at killer performance, up there with Justin Keith and his crew, and those guys are stuck too!!! I sure hope I get this thing figured out. Thanks for the advice. Ill keep you guys updated.

[Keithj3]

Gonna try fresh gas soon as they open. And I’ll make sure they check the coil connector too.

[Keithj3]

Well guys put fresh gas in the car. Nothings change who can I pay to figure this thing out!!! I’m all ears!!

[L78toLT1]

When I lost fuel injection on the rh bank, the issue was a bad ecm