All of the sudden one day when driving slowly then moderately accelerating under load, AFR goes to 10 or below and the car misfires. It cannot go into boost at all and also needs to be driven very lightly to avoid this problem. Vacuum is normal. Everything else seems normal and usual.

I cleaned all four plugs, and it didn't help. I then checked all plug wires and they were fine. Then I looked under the coils. They had the slight burn mark on the bottom of all four so then I replaced all four coils with the MSD LS2 coils. I also replaced all the plug wires with MSD wires and cleaned the plugs again. I reset the computer.

All of that didn't help. I then replaced the two leading plugs (shop didn't have the others in stock). This didn't help. The next day I changed the other two trailing plugs with new ones also. This didn't help.

I then took the bumper off which is what I should've done first and checked all couplers. I found one hose clamp loose and one coupler with a slight tear. This was obviously the source of the problem I thought. I replaced these and most other couplers with 4-ply reinforced silcone couplers and replaced most hose clamps with t-bolt clamps.

I'm not sure if this helped, but I drove around, gave it some throttle and had the same problem. I found that one of the couplers I didn't replace slipped off. I put it back on snug but the problem is still there. There are a few couplers that I cannot get at because they are WAY inside. The few that are on the turbo and the one right after it. I tried to wiggle them and visually inspected them and they look fine, but I can't see every angle. I will re-inspect all couplers again in the daylight but I've already done that twice now with a flashlight.

The other couplers I couldn't replace simply because I can't seem to stretch the new ones into place. But these couplers are in plain view and fine. They are the two directly after the throttle body.

I then disconnected the battery for ten min and reset the computer again. I still have the problem.

I was wondering if I could get some recommendations on what to try next. I have no experience or special tools so I was looking for suggestions for what I could try at home. My car is turbo'd with the greddy kit and GT3071R. Thanks!

 

I also just checked the BOV, it's fine and re-checked and tightened couplers. I took my intake apart and checked it also, took out and cleaned my MAF. I also tried to wiggle the wastegate actuator arm and it felt stuck. I don't know if this is normal. I read somewhere the wastegate could get stuck sometimes or have a stuck or messed up spring. Should I check the compression the rough way by listening to the souind coming out of the spark plug hole? Now I seem to be able to get into boost, but it goes super rich and misfires in boost or moderate load. ...

 

What are your load and MAF values like....everthing else log normally?

 

sounds like my exact problem i had before i removed the turbo kit....your symtoms def. sound like a boost leak...when i was removing my turbo kit i found a break on the seal i made for the metal plate that goes between the intake manifold...my suggestion is to perform a presure test and see if you can get a leak to occur

 

I will get on that log tonight for sure!

I also thought for sure it was a boost leak, especially after I found the loose clamp and the small tear. What I am hoping now is that there just wasn't enough drive cycles for the car to 're-learn', because the symptoms are slightly different now than before since I can actually get into boost. I've reset it many times before without this problem though, but read that we can get inconsistent results after resetting.

 

Vacuum test @ idle/compression test

 

The more days go on the more I am convinced it was just that I didn't have enough drive cycles in after the battery pull reset. I didn't realize that I'm needing something like at minimum over 25++ drive cycles over a few weeks time. It seems like it's getting smoother and smoother and the power is really coming back. I can gently get up to 5 lbs boost now with no misfires.

Now I remember it did take a while after the last time with the battery pull reset but back then I was running lean and had detonation, then paranoid, I drove it like a granny for two to three weeks, and after that I couldn't repeat the detonation event. I guess this time after re-adjusting my intake it's on the rich side but it's going away slowly.

When I reset using the AP, I usually don't need many drive cycles at all for the car to run normally but I guess pulling the battery terminal is much different. I guess it's probably in the manual somewhere... I guess I was looking for an instant solution to the problem but the solution isn't instant. I think my problem was the boost leak from the loose coupler that is now fixed. I hope this is all it was.