2003 GMC Sonoma ZR2 4.3L - This may be a tough one but here goes. I just bought this truck and have a question about a possible transmission component problem. When driving at 50-60mph and encountering a hill, the truck does not kick down the transmission unless I really apply more gas. The 4 speed auto trans is always trying to reduce rpm's to increase fuel mileage (runs about 1400 rpm's at 55mph) but when it encounters a hill it will loose speed before it will kick down the transmission. I have to manually do it to regain speed. I am not sure if this is normal or is there a sensor that should sense this load and automatically control the trans. Any help would be greatly appreciated.
The transmission is this truck is a 4L60E. It is electronicly controled through several sensors. It will sense the load on the motor mainly through the TPS (throttle position sensor).It is not uncommon for you to have to really press the gas to make it down shift. Alot of the feeling depends on gear ratio in the rear end. The 4.3 is a very good engine, but it combined with a high gear rear end and overdrive may really seem under powered. You can put a programmer on it to change all the shift and power feel.If you are not having a hesitation issue then it will most likley not be the tps. You may just need a fuel and air filter, not knowing when it was last changed. The programmer is the best way to get the feeling you may be used to. Good Luck
I mean like a chip, hypertech, It is a performance enhancing device. They work and some are adjustable to control different things. You might research them a little before you invest in one. They are worth the money and the one I put on a 300,000 mile 1996 Ford power stroke diesel boosted my milage by 4 mpg. I know that does not sound like much but it is a one ton with 4:10 gears that gets 17mpg. It is adjustable from 60/80/100 horses.At the 60 horse setting it does best for every day driving. After that the milage drops. Good Luck
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Thanks for the reply. All of the filters are brand new. I have gone through the entire truck and replaced all of the main components. What do you mean when you say "programmer"?
Thanks for the reply. All of the filters are brand new. I have gone through the entire truck and replaced all of the main components. What do you mean when you say "programmer"?
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