Thread: powertrain issue has me stumped

first off, hello, I'm the new guy ! I bought my wife a 2006 Grand Prix a few months ago with about 115k on it, body is in great shape it looks like the car was well taken care of. first symptom was the remote start would turn over briefly then not start and the lights flash. so I put plugs and wires on it (PITA) And that didn't help. So i said it's probly the battery, and as it's gotten colder out ive noticed sometimes the engine wont turn over on the first attempt, and it wont fire up if it's only turned over breifly. all that makes me think battery until tonight, she was stranded beside the road so i came from work and checked it out. she said she was accelerating from a stop and the car started bucking every time she pressed the pedal and the Tach was going from 0 to redline irradically but she couldn't hear the engine actually revving. I suspected transmission given the milage. the fluid is brown and smells like play-doh/menstration mix but the level is right on the money so it isn't leaking or burning off any. So i drove it and it was fine, Could not duplicate. My immediate thought was torque converter shudder, but that wouldn't just go away. My next thought is that the Tach bouncing is some kind of telltale diag for something, fuel pump maybe. No CEL which makes things really fun. I know a trans service would only help things but i don't want to drop 80 on fluid and filter, then have to replace a trans. I am a technician, but I am a Chrysler tech, so I really don't see GM ever.

Start by cleaning the MAF w/ the appropriate cleaner. May also want to remove the throttle body and clean it till it shines. The TB's cause all sorts of strange issues on the 04+ cars when they are dirty. Make sure you clean the entire thing, not just spray the front of the butterfly. Being DBW, the TPS could be bad as well.

Beyond that it could be a crankshaft position sensor. Those often throw no codes when they start to die.

Agreed with what the others have said. Clean the throttle body (it's easy), clean the MAF with the right cleaner, and get the battery/alt tested. The battery is right on the edge of that 7 year life span. Also, sounds like the trans fluid really needs a change. Just don't get a power flush. That killed the tranny on my old car. If you're handy, do a pan drop and replace the filter yourself. Dropping the pan on this car gets most of the fluid (almost 8 quarts for me), but it's better than driving with crap burnt fluid. I think the GM official procedure is to drop the pan three times over a certain number of miles. I too the time to add a drain plug to mine so I can just drain the fluid next spring.

ya i was planning on a trans fluid change but it's hard to get an open hoist after work because it's 4wd season up here and we have alot of transmission jobs going on so they generally stay on the lift for 2 days. Is there anything better than the delco battery? cleaning the maf today and i'm pretty sure the alternator is good, it charges at about 14.5v but overnight with no loads the batt voltage drops to 11.3v range

I bought a Road Runner. I had to adapt to side post terminals, but I saved $60 by ditching the glass mat Delco battery. And I ended up with 850 CCA, 130 more amps than my stock battery.

i cleaned the maf annd throttle body, although the maf looked fine. throttle body was disgusting. now to find a decent battery.

Originally Posted by NegativeOne13

Bahahaha quote of the day!

Filter and fluid can be done very easily... just jack it up and put jackstand under it.

sir, i am not doing it in my driveway, i will drive it to work and put it up after hours and use all my overpriced tools that get **** done faster, but yes that's the exact description of the fluid, i'm pretty sure it's described that way in the service manual:"When transmission oil becomes brown and smells like play-doh/menstration, service is required."

quick update. yesterday after a bad day at work, my wife calls me and says her car has no power steering. I immediately said don't go anywhere! so i got to her and opened the hood AHA! the belt was knocked off, so i stasrted wiggling things, water pump pulley was trashed. so I went out and got a battery and the water pump and associated crap. did the repairs and flushed the cooling system. so, i will keep posting if the chuggaluggin happens again