RPM Surging Between 2000 - 2500 RPM

[goldberg_52403]

69ELCamino, can you list what motor you have and miles? Also, is this the diagnosed problem, what is driving you away from the tcc solenoid? Is the problem more severe?

Thanks.

[goldberg_52403]

I should have looked at your post a few threads down, I see you have the 3.1 and put the rebuilt in yourself. Did the rebuild come with new solenoid?

Thanks, just trying to get an idea about my solenoid/tcc.

[Krule]

Hello, i purchased a 1999 grand prix Gt about 6months ago, and it seemed like i had the exact same issues, the surging but only when climbing hills, the rpm would be surging up n down at 2000 up n down by about 200, and just recently today while i was driving back home something in the front of the engine started clugging like metal on metal very very loud and i was only 1km from home so i drove it and then i parked the car at my place. tryed to start it up and the engine made the crazy sound and then hit the gas just a tad and that was it, no more shifting! it just gave out. Even when the cars off i can pull it into Drive and push it around. When i try to start the car now it wont even start, it doesn't even turn, the lights dim it makes the electrical sound like it's right about to crank and nothing. Wont start. just hit 394K it's well used i suppose. Recently had the oil pan gasket repaired (2months ago) at dealership. I have no idea what to even begin looking for, i've got a buddy coming over tommorow afternoon to take a look.. not much to see though. Any suggestions on what i should do?

Thanks, kyle.

[Krule]

Timing chain snapped, and wrecked everything with it. At 394k the engine is offically toast. dealership wants 1500$ labour for an engine swap (89$ n hr at 16 HOURS LABOUR) 700$ at a backyard mechanic i know give or take a couple dollars. picking up a 200k engine for 400$ tommorow, from a 98 prix to my 99 prix, best bets to get a compatible engine, 96 le sabres 3800 i looked at had the heating pipes coming out different + wiring harness is different + mounting. So if your swapping an engine try n get a decent prix one for your prix. so 400$ + 700$ x 1.14 = 1300$ roughly. Also a refurbised or remanufactered 3800 from the dealership is 3100$! LOL! i could buy another prix for that.

[Enzy]

Well, I've now replaced my tired old plugs with AC Delco irridiums and the coil resistance checked out OK. The car starts better with the new plugs, but still the same surge problem. I also did a little more road testing and confirmed that it still surges when manualy shifted into 3rd (D). I assume this would rule out the TCC solenoid since the TC only locks in OD?
I'm holding off on replacing plug cables since mine aren't that old.
Any chance the MAP sensor could cause this?

[goldberg_52403]

I am pretty much in the same boat, although I am pretty sure its my TCC solenoid. My question is, could a bad wire cause the TCC solenoid to occassionally act up? My car runs beautiful 75% of the time (I drive on the interstate 60 miles a day), but sometimes acts up under gentle acceleration in OD (about 1/4 of the time). When I first got the car, the SES light came on and a wire had to be replaced at the TCC, and the light went away. Ironically afterwards I am having temperamental issues with the TCC, but no SES. Could this be related?

Thank you.

[goldberg_52403]

I actually just found a very in-depth website that has a lot of detail about the 4t65e transmission. Take a look here:

http://www.tripleedgeperformance.com...ssion_Info.php

Has anyone been here before? They do have a section in regards to my issue:

Tach bounces up and down a few hundered rpm while cruising in lockup:
Another common problem / concern of this transmission and more pronounced with added engine power or higher mileage. This generally happens when the valve body has excess wear in the TCC valve area. Excessive fluid leakage in this area of the valve body causes TCC apply pressure loss and can lead to uncontrollable TCC operation which causes the engine rpm to bounce up and down a bit. This problem is noticed most after driving a while and speeds between 42 and 70mph and in 4th gear. There are other causes to this problem that can be from worn or shrunken teflon seals on the input shaft, a bad o-ring on the input shaft that seals in the torque converter, a faulty torque converter clutch, and even a bad pressure control solenoid. Another common occurance is a worn out sleeve in the channel plate that supports the input shaft. When this sleeve wears the input shaft will get chewed up where the sealing rings are and cause problems. Commonly code P0741 will be found in the pcm memory as a stored code and is described as Torque Converter Clutch Stuck Off. When this happens adaptives shifts are disabled, TCC operation is disabled, and 4th gear can be disabled. Generally a new or reman / repaired valve body will correct this condition and a new EPC solenoid is always suggested as well. The TCC/PWM solenoid is rarely ever at fault and I am yet to find one bad. Again the valve body is the common cure BUT not always the culprit and certainly not the whole problem after this has been happening for a while. Any time a torque converter fails there will be debris going back into the trans. There is a pressure relief valve in the channel plate that will collect debris from a bad torque converter and reduce cooler flow, cause trans to run hot, and greatly effect TCC operation and can destroy a new converter in a matter of miles if this isnt carefully inspected or upgraded. The best way to verify proper operation as commanded by the pcm is with a scan tool by viewing TCC slippage rpm, TCC duty cycle, EPC data, and checking any codes and making sure the engine is running properly and a misfire is not a false sense of a torque converter problem or shudder.

I think I am going to take the car to a transmission shop tomorrow and see if they can scan my transmission. I would hate for it to be the internal parts, but that would actually be covered under my warranty.

[yakman]

Any solution on the car ? I would really like to know !
Mine is exactly the same !!

[goldberg_52403]

Unfortunately I have not been able to fix my car yet, just financial reasons. My issue isnt incredibly bad, just annoying when driving on the interstate. If it begins to get worse, I will definitely have to take it to the tranny shop.....

Good luck!

[Enzy]

I have not proceeded further and am currently 'putting up with it', manually shifting down when the engine starts hunting. I will follow Goldbergs advise and have a scan done when I get a chance.
Please let me know how you make out.