I have an '07 SS S/C and on saturday, i started it up (cold after sitting through the night) to have 'eng pwr reduced' and it idles awfully and the whoel car shakes violently like 3 of the 4 cylinders are misfiring! after a few start ups of the same thing it starts up smooth as glass but i have a DTC. I'm under warranty for another 80,000mi or 3 1/2 years, no biggy. but it's saturday on a holiday weekend and college starts for me on tuesday.

by the end of sat night, the mil light is gone (after 3 small trips to a few places, full warm up and near full cool down) so i'm hoping it was a 1 time thing. sunday morning, same scenario again! only this time i see the engine power reduced on the display b4 i start it. i figure it's a sensor thing, i get it running again same thing, after 3 or 4 awful start ups.

once i'm up and running i get to autozone to discover i have a p2101 error code - Throttle Actuator Control Motor Circuit Range/Performance

i get back home, mil still on, and i removed the TB, cleaned it, checked the wiring going to the TPS and it looked fine. i also checked for water or corrosion in the TPS connector, none. reattached, replaced TB, started the car, perfect. the code was gone as well (note: i never disconnected the battery)

i go to a friends house, and after 3 hours sitting THE PROBLEM IS BACK. i'm at a loss. (i figured when i cleaned the TB i just got lucky in that the car didn't experience the problem upon startup, and that i didn't fix anything.) i'm assuming one of the following after reading up on this:

-the throttle plate is binding still even cleaning with TB cleaner, though unlikely.
-the TAC motor is spazzing out on me either due to a crimped/corroded/loose wire in the TPS harness/connector somewhere.
-my TPS is malfunctioning.

i'm hoping it's not a sensor, but i can't due much else on my end cept wiggling the wires to the TPS while i idle to try and simulate and isolate the problem. any1 with a similar experience or with further troubleshooting ideas that can help shed some light on this would be much appreciated. tia.

 

it probably is a sensor and under warranty wouldnt worry about it , just be gentle on the way over to the dealer

 

it is most likely it is the TPS as you suggested rodimus, checked out everything i could. the plate is perfectly fine, as are the wires headin to the TPS. when the car was idling smoothly i jiggled them a bit, no problems. i just hope it won't mess me up for my commute to college tomorrow.

i cleared the code manually this time by clearing the ecu (via +bat to ground) and i hope it'll disapear for good this time! although since problems love to be sporadic, i have my digicam in my car, ready to go for when i get 'eng pwr reduced' @ ignition. i also have my lil autozone dtc code printout! then the dealship won't bust my ***** if i bring it in.

 

even after clearing the code, engine power reduced comes back. i noticed that after i start it a few times, it's fine. goes away completely until the car is turned off.

I was thinking perhaps the bushing in the TAC motor is loose or faulty, and when the connection warms up a bit from the current supplied, it works properly, hence why the problem is intermittent. just a guess, but it makes sense because on a quiet night like tonight, i can hear a tiny lil electrical whine, sort of like a groud loop in an audio system, but much more faint. thought it was a leaking vacuum line at first, but it's coming from the TB and i checked every vacuum line.

under the warranty, chevy provides free towing to a dealership if the car is undrivable, so i'm calling tomorrow morning when the dealships open back up and having them pick it up. hopefully it'll be resolved quickly, and i'll post with the solution so any1 else with p2101 dtc and 'eng pwr reduced' can solve this issue quickly

 

so i bring it in on tuesday, chevy found a diff code i don't have the docs in front of me, but for p16something, bad ignition switch, replaced, went on my way. wednesday morning, it's back! WTF! turns out the ignition switch really was bad so they replaced it thinking that fixed the problem that just so happened not to surface.

bring it back wednesday, keep it overnight, p2101 was the culprit of course... they replaced my whole throttle body. (picked up car after the service counter closed, got the keys from sales) i didn't get a tech answer of the problem. i had a binding throttle plate.

as a reminder to people who get this error code and eng pwr reduced, check ur codes. also clean your TB and check the wires going to the TAC module and TPS! you might avoid a trip to the dealer.. but if you're under warantee, who cares =P

 

Thank you very much SprChrg4Life!!!! I just picked up a coffee through the Timmys drive through and buddy at the window ask me to "light em up" when I left so being the donkey I am I did just that, but a problem occured. My car just dies on me and I get this trouble code "Engine Pwr Loss" w/check engine light on and I tried starting the car and it was running sooo rough and kept stalling. Eventually I was able to get the car to my garage at my store and after reading your post I checked the connectors and sure enough the connector to the TB which by the way is very hard to see without actually getting your hand under it and feeling around was totally disconnected. I was shocked because I recently cleaned my TB and I knew I plugged it back in properly but something dawned on me. I just had my car in for an oil change today and because of the ridiculous placement of the filter I assume the guy at Lube-X disconnected this plug and didnt realize that he didnt plug it in all the way and it must have popped out. Thank god for you though cause I was ready to pick up the phone to call Chevy roadside and have it towed to the dealer. Nice post and thanks again, Nathan

 

I am having the same problem. When I was trying to acclerate the problem just showed up. The engine turned off. I tryed to start but the hoorible noise came out and the engine did not start. It is strange that the problem appeared during my driving. DO you think it is a problem with TB connection?

 

thanks angel, glad the post could help you as for you atu, do what we did to trouble shoot it all... i could only go so far because it was the TAC motor after all in my scenario, and it was replaced.

1) check the throttle plate. does it bind anywhere? does it stick? does it have a spring force in both directions from its neutral position (which is slightly open)?
2) with the air filter piping disconnected, put a few layers of some sort of very thin mesh screening over the TB, to slow down the air rate going in to emulate an air filter, so that you can see throttle plate movement (ya might throw a lean code due to too much air, dissconnecting the terminals on the battery for a bit should fix that) now have a friend hit the gas, is it moving? put it to 3k then depress quickly (to put it in vacuum) to see if it rotates fully closed.
3) check all connections. it's easier to unbolt the 4 bolts on the TB and disconnect the connector on the bottom by turning it around. getting to it without taking it off is a pain, plus... it's only 4 bolts!
4) while it's disconnected, clean it! use some TB cleaner and microfiber cloth to remove all the gunk.

reconnect, reinstall, try again. if it's gone, good. if not, well i assume you have an error code go to chevy (if under warranty) or go to autozone if not. post the error code back here and we'll go from there.

 

wow It works. It was a problem with connection. I am going to clean air filter also.

 

glad to help. this is a problem usually associated with the connection to the TB, or a bad TPS or TAC Motor. faulty ignition switch can be the case sometimes, but most likely throttle body related (chevy tech told me this!)

np let this be a reminder to you... do your own oil! if you want something done ya gotta do it yourself. these TB plugs are a bitch to get off when you want them off, yet they pop off randomly! oh and don't do burnouts at fast food places... didn't you see the drug-free america commercial where they hit the girl @ the drive-thru cuz they're higher than a ****** kite? lol. and don't hit the fat bitch walking in to start her shift either, you'll dent your front bumper!!

 

faulty barometer can also cause those symptoms as well.