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00 GP More Strange Behaviors

GT2000

GT2000

Donating Users
Well i have made two older threads regarding this car and the little what u may call "idiosyncrasies" it has. Front high idle when you first start it, to a unsteady idle when warm, to goofy transmission behaviors. Well this happens to be another goofy transmission behavior, but a much more noticeable one. This morning i drove the car into town maybe 15-20 mins one way. The car always waits until it warms up some till it does what i presume is locking the torque converter, my grand am does that too, few minutes of driving at the most. Well it would not lock up the whole way into town! Im going 55 and its revving up high, and im thinking "okay, go ahead, shift" but it doesn't, let off the gas, rpm's fall, get back on gas and go way back up, at 55 should be running under 2k and im turning just under 3k. Temp was where it should be. It wasn't locking because i shifted to 3 and it raised the rpm even more, and back in to O/D still wont lock. Still shifted smooth and normal. Went into town, did my things, came out of town got it up to 55 and no issues all the way home.
 


The only way an EFI engine can gain RPM is by adding extra air, and if your not pushing down the accelerator with a foot to open the TB, then either the IAC is malfunctioning, or you have a vacuum leak, FIX that first, then move onto the transmission if it is still acting up.
 
Car has 48k miles, was taken care of and fluid looks good, doubt highly its in the trans. Like i said and i have made other threads about little issues with this car, but was never able to find why. No codes to help or anything. Feels like Torque converter aint lockin up. But on way home it was fine. I let of the gas and rpm would drop and then get back on gas and they go up must farther then they should. I dropped it in third and it dropped a gear so it must be going into 4th. I wouldn't be surprised if this is somehow related to the other issues i've had, i just cant find the problem.
 
Simple way to tell if it's TC lockup (which it's not) or if your 4th clutch hub stripped, while driving normally at 55mph don't move your foot off the throttle and just barely touch the brake. Enough that the lights come on but not slow you down. If you you see the rpm come up about 500rpm your torque converter is fine. Then while driving along at that same 55mph pull the shifter from D to 3 and see if your rpm jump by 1000, if they don't you need to replace the 4th clutch hub.
 
This car some days will work fine and act normal, the next it will not behave till i get to town, some days its fine some not. Also more fun little crap that it does, when u start it when its completely cold when it sat for a bit, it will start up and rev way up, and then sometimes when its warm, it wants to crank long before it sputters slightly and starts. Now tell me if i am wrong, but these cars have a system where they are suppose to start with basically a bump of a key, hardly any cranking. Our 98 used to be like that, started instantly, but my GP has NEVER done this, always cranked longer. Warm idle is floaty 800-1000rpms floats around, cant decide where it wants to be. I know I've mentioned these same issues over and over, but i just want to figure out what's wrong, no codes, not much to go on. OH, almost forgot something, is it weird that it will only sometimes the RPM's will flare up right when it shifts to O/D
 


When was a tune up last done (plugs/wires)? Clean the MAF? Clean/replace the IAC? Remove and clean the throttle body? Change fuel and air filter? Check for vacuum leaks?

I had an issue with my 00 GT similar to yours once and my fix was removing and cleaning the TB until it shined on the inside, clean the IAC, MAF, new air filter and fixing the vac leak at the connection from the brake booster hose to the UIM.

I've always let the fuel pump prime before I start it up and it fires off right away. If I just jam the key in and turn it, it will take a few cranks to fire off. Seems normal to me. I usually just let my fuel pressure gauge come up and then hit the key and it fires right up. About 3-4 seconds wait. I know you don't have a FP gauge but give it a try and see if it fires up more quickly.
 
MAF was cleaned, Air and fuel filter done, i checked for vaccum leaks, didnt find any. Guess i could try the iac next
 
Well, I guess it would help if all the Upper Intake manifold bolts were in tight???!!!:th_scratchhead:

Was hunting around for vacuum leaks AGAIN, and saw a bolt on the intake sticking up, the one closest to the throttle body on the front of the engine. Went and pulled on and it CAME OUT?!?!? It was just sitting in there, not threaded at all! :th_hammerhead2:
Im dumbfounded because this car was serviced at a dealer since new with one owner. I never messed with anything with the motor, and it has 48k miles, so who was in there???? Anyway, I tightened it down to torque specs, and cleared data in the computer. Took er for a drive and it seemed much happier and smoother, didn't studder on a pullout. Only drove 15 mins, so time will tell, because around 3k RPM or higher i get a wistle-whine now from the motor, almost like a turbo, sounds kinda cool actually, that wasn't their before?? MAP psi is up slightly too, was 4.5ish at warm idle, now around 4.8 4.9.
 
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