Reduced Engine Power

OL Yeller

OL Yeller

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Feb 11, 2019
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So..I cleaned my MAF sensor and Throttle Body a week or so ago and when I put it all back together and started the engine, I ended up with several codes. One being "reduced engine power", After some research I deduced that it was an issue with the throttle position sensor. Turn the car on and within a couple seconds it goes to 2000 RPM and stays there. Clear the codes through the DIC and it goes back to idle for a couple seconds then back to 2K again. I bought a new TPS (AC Delco) and installed it but still the same thing. I have tried several of the recommendations off forums and Youtube, but to no avail. Surely, someone here has encountered this issue at some point and has had the issue fixed.

I would like to know what has to be done to reset the TPS or fix the issue, as I am itching to get out on the road.

I am the furthest thing from an electrical technician, but would appreciate some insight on how to remedy this problem.

I thank you all in advance,
 
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That is not good to hear. With my old Camaro, one of the so-called free mods was to de-screen the MAF. But doing this risked damaging the MAF. The oil from K&N air filters used to be notorious for damaging MAFs at one time also. If the MAF is damaged from cleaning then you may need a new one. Fingers crossed it is a simple fix.
 
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12cents said:
That is not good to hear. With my old Camaro, one of the so-called free mods was to de-screen the MAF. But doing this risked damaging the MAF. The oil from K&N air filters used to be notorious for damaging MAFs at one time also. If the MAF is damaged from cleaning then you may need a new one. Fingers crossed it is a simple fix.
Click to expand...

I hope that isn't damaged... that's the last thing I need at this point.
 
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12cents said:
That is not good to hear. With my old Camaro, one of the so-called free mods was to de-screen the MAF. But doing this risked damaging the MAF. The oil from K&N air filters used to be notorious for damaging MAFs at one time also. If the MAF is damaged from cleaning then you may need a new one. Fingers crossed it is a simple fix.
Click to expand...
I had this happen to my Wife's Lexus RX 300 after adding and K&N air filter. Fought with it for a while and finally got rid of the K&N , installed a new MAF sensor and lived happily ever after.
 
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OL Yeller said:
So..I cleaned my MAF sensor and Throttle Body a week or so ago and when I put it all back together and started the engine, I ended up with several codes. One being "reduced engine power", After some research I deduced that it was an issue with the throttle position sensor. Turn the car on and within a couple seconds it goes to 2000 RPM and stays there. Clear the codes through the DIC and it goes back to idle for a couple seconds then back to 2K again. I bought a new TPS (AC Delco) and installed it but still the same thing. I have tried several of the recommendations off forums and Youtube, but to no avail. Surely, someone here has encountered this issue at some point and has had the issue fixed.

I would like to know what has to be done to reset the TPS or fix the issue, as I am itching to get out on the road.

I am the furthest thing from an electrical technician, but would appreciate some insight on how to remedy this problem.

I thank you all in advance,
Click to expand...
There is another sensor involved besides the TPS. I have had trouble with it myself on my C4. The idle does not stay at one RPM when this is faulty. This part, which I don't recall it's name, takes a long time to replace and it requires a lot of dismantling which could mean a lot of broken bits if not careful. The idle is adjustable with an allen wrench. (just like the old days)... There is an allen screw near the throttle plate/spring area. If you turned this counterclockwise 1/2 turn your car would not jump up to 2000 RPM, it would be lower. I adjusted mine and it is very livable at idle. I haven't had to change the part I'm describing.

When I cleaned my throttle body I did not spray any cleaner directly into it. I sprayed a clean rag and wiped it clean as far as I could reach. In your case, it sounds like you have dirt of some kind you loosened up that wasn't a problem before. It may clear out on its own. If changing the TPS did no real good, it is not the problem.
 
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Any codes?
Try to check if one of the 5 wires going to the MAF isn't pulled out of the connector not doing contact when you plug it back in...
 
Corvette GT1 said:
Any codes?
Try to check if one of the 5 wires going to the MAF isn't pulled out of the connector not doing contact when you plug it back in...
Click to expand...
GT1...here's the codes i'm getting:

PCM - P1120, P1220, P1516 and P1518
TCS - P1278

DIC is saying Reduced engine power, service traction control and service active handling.

I have a guy that's going to drop by on the weekend that used to be a GM technician that worked mainly on electrical issues, so I hope he can find the problem and we can get if repaired.
 
The problem with altering the throttle body, even trying to clean it, is that many sensors meet at it. The throttle body on a C5 alters many things with the computer. The different driving modes and other characteristics of a C5. If changed from spec in any way, your awesome yellow Vette will drive like a 1971 VW Bug, lol... Chances if you put a new throttle body on, all issues would disappear.. However, an expensive piece to purchase from GM, I'm sure.
 
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Update: I unplugged both sensors from the throttle body last night and went out to the garage about 2:00pm today started up the car and the idle went to 2K rpm again....cleared the codes again and the idle dropped to 1K rpm. Had it running for about 20 minutes stayed at around 1000 rpm...shut it down started again about about 5 min later and still at 1K rpm. Got in to go for a drive but had no throttle response, back into the garage again. Hopefully my GM mechanic friend can figure out whats wrong with it when he shows up in the next day or so. I will be back with another update, stay tuned.
 
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OL Yeller said:
So..I cleaned my MAF sensor and Throttle Body a week or so ago and when I put it all back together and started the engine, I ended up with several codes. One being "reduced engine power", After some research I deduced that it was an issue with the throttle position sensor. Turn the car on and within a couple seconds it goes to 2000 RPM and stays there. Clear the codes through the DIC and it goes back to idle for a couple seconds then back to 2K again. I bought a new TPS (AC Delco) and installed it but still the same thing. I have tried several of the recommendations off forums and Youtube, but to no avail. Surely, someone here has encountered this issue at some point and has had the issue fixed.

I would like to know what has to be done to reset the TPS or fix the issue, as I am itching to get out on the road.

I am the furthest thing from an electrical technician, but would appreciate some insight on how to remedy this problem.

I thank you all in advance,
Click to expand...
Why did you clean your MAF for? When you cleaned it, was there some kind of screen in it yet? Did you let it sit overnight before installation? MAF is very fragile and if you're not careful you'll have some issues as you are having right now. Perhaps by cleaning it again and let it sit for 24 hrs. might solve the issue. Good luck.
 
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