throttle position sensor and transmission problems

[Blackstripe]

I have a 2002 Silverado 4.3, 4L60E. I had misfire issues and replaced a bunch of sensors & components. Some GM and others aftermarket. The truck started having a high resting idol of 1500, which was annoying in traffic. I was used to the 700 RPM and not having to keep on the brakes. My transmission was also starting to act up. It was shifting up into overdrive way too soon. The fuel economy was also in the toilet. If I gave it hard or full throttle it would shift fine, but normal driving it would shift through all the gears, each too soon, bogging the engine down. I knew I had already replaced the throttle position sensor (with an after market one) and did not consider this. so I started replacing & cleaning other related idol sensors. I finally read that other folks had been having issues with aftermarket TPS's. I ordered a genuine GM TPS and installed it, unplugged the negative terminal so the computer could reset, went the 100 miles, and have had no issue since. Now the trans shifts fine, idol is back to normal & fuel economy is back. Just a FYI, in case someone else has the same issue. Aftermarket (JUNK) TPS: $18.00, GM TPS: 42.00, Years off my life: PRICELESS!!

 

The misfire was the EGR valve, which I replaced after replacing the TPS, which made this home garage diagnosis very annoying. Misfire went away after the EGR was replaced. But..... now I had these other issues. I was throwing parts at the problem, replacing anything that could be related for the engine and trans, so if anything could be learned, do not get inferior parts, it will make small issues like this expensive.

[2017HD]

Glad you found the problem. I had something similar with my then new 83 S-10. Back then there was a TV cable that ran between the throttle and the transmission - it was miss adjusted from the factory and it caused the transmission to upshift very rapidly and not downshift unless you floored it. Like you, it made for both drivability and fuel economy.

[aerojar01]

I have a 2002 Silverado 4.3, 4L60E. I had misfire issues and replaced a bunch of sensors & components. Some GM and others aftermarket. The truck started having a high resting idol of 1500, which was annoying in traffic. I was used to the 700 RPM and not having to keep on the brakes. My transmission was also starting to act up. It was shifting up into overdrive way too soon. The fuel economy was also in the toilet. If I gave it hard or full throttle it would shift fine, but normal driving it would shift through all the gears, each too soon, bogging the engine down. I knew I had already replaced the throttle position sensor (with an after market one) and did not consider this. so I started replacing & cleaning other related idol sensors. I finally read that other folks had been having issues with aftermarket TPS's. I ordered a genuine GM TPS and installed it, unplugged the negative terminal so the computer could reset, went the 100 miles, and have had no issue since. Now the trans shifts fine, idol is back to normal & fuel economy is back. Just a FYI, in case someone else has the same issue. Aftermarket (JUNK) TPS: $18.00, GM TPS: 42.00, Years off my life: PRICELESS!!

 

The misfire was the EGR valve, which I replaced after replacing the TPS, which made this home garage diagnosis very annoying. Misfire went away after the EGR was replaced. But..... now I had these other issues. I was throwing parts at the problem, replacing anything that could be related for the engine and trans, so if anything could be learned, do not get inferior parts, it will make small issues like this expensive.

I had a similar problem on my 5.3 with knock sensors. Bought aftermarket still had issue. Returned those and bought genuine GM from the dealer and it resolved the issue.

 

Sent from my SAMSUNG-SM-T337A using Tapatalk