Need help with stumble under boost problem

[SlickTR]

Well its not the plug wires and i tried a new MAF as well just to be sure and it wasnt the issue either. To top it off now the torque converter is randomly not locking, 4th gear indication wont light up even though it is going to overdrive. The transmission is almost brand new i dont think its the pressure sensor. Sometimes i can shift to 3rd then back to 4th and looking at my DS the 4th gear indicator will light up but as soon as the torque converter locks the 4th gear indicator goes out again BUT the converter stays locked, until i let off or brake of course lol. I dont know. Dont even know if this is related, but it makes me think i have some type of electrical gremlin now. I've about had it and really feel like going into the garage and lighting the damn car on fire.

 

[SlickTR]

Double post

 

[SlickTR]

Old thread I know...but I realized I never updated this, figured it might help someone down the line...

The car sat for a while while I was deployed, got home and pulled the valve covers, figured i'd check the springs, check for a possible wipped cam, etc. This is something I should have done earlier in the trouble shooting process. Well immediately I notice that the plastic rocker retainer for #1 exhaust side is missing, it had broke and was laying by the spring. Rocker was still over the push rod and activating the valve however. I fixed the rocker retainer and the problem went away. Since it idled and drove fine out of boost the best I can figure is that under boost and higher rpm the rocker had enough movement that the valve floated or the cylinder dropped all together.

Anyhow, lesson learned, if your car has similar issues and the normal stuff is not working, pull the valve covers and take a look lol.

 

[zhorner]

Thanks for the update, i literally logged on to start a thread titled "My Car is F*cked" about the exact same problem. I was getting on it pretty hard last night and the tranny flared during a 20# boosted shift...something gave and the car almost died. i limped home @ 50 mph anything higher it starts to build boost and stumbles hard like you described. i already checked all my couplers and chip with nothing wrong with either. Ill check my turbo tomorrow and go from there...any more suggestions would be helpful as i am no mechanic.

 

[BlackBandit]

Do yourself a favor and do a compression or a leak down test. A rocker arm not hitting the valve right can cause some problems with the seat. Not saying you won't be ok. If it was me Id want to know if one cylinder reads a little low even if you didn't fix it now. You know, just in case I'm trying to diagnose a problem down the road.

 

[NOTSOFAST]

how do you know the coil/modual are good? I had the same issue a while back. I had coil/modual tested & it had tested good, would read 11.3-13.5. but under stress it would spit n sputter. I replaced with new AC-Delco & I was once again a happy camper. so even though you think your coil/modual is good, in reality it may not be.

 

[zhorner]

Update: I took a second look at my intercooler and the drivers side mount ripped off and had about a nickel size hole in it. Took it to a radiator shop and he welded it on and fixed a few other minor leaks and the buick has never run better.

 

[GNRick]

Update: I took a second look at my intercooler and the drivers side mount ripped off and had about a nickel size hole in it. Took it to a radiator shop and he welded it on and fixed a few other minor leaks and the buick has never run better.

What could have caused that?

 

[zhorner]

the bolt that mounts it on that side wiggled loose and after driving for so long with it partially in it bounced around cracking the welds...that + over 20 lb boost and boom, instant dodo.

ultimately its my fault for not checking my stuff like i should but lesson learned.