Goes to fourth then locks up way too early. Let off and it kicks down?? [Archive] - GrandAmGT.com Forum


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12-25-2008, 09:46 PM
Ok 2002 grand am se 2.2 with 160,000!! Just hit it today. Over the past few weeks, I have noticed a small problem. If I am driving in town, slowly accelerating to around 40 MPH, with a steady pressure on the peddle, it will shift into overdrive, then like one second later, the converter will lock up. I can actually watch the tach go from say 2300 RPM, down to 1900, then 18,17,16... Even with no change in pedal. The power of course goes away. So, if I slowly press the pedal down, I can almost get it to the floor, and it will never pull out, it just lugs and bogs with out shifting down. When it happens, I can just barely tap the pedal and it will stop, jump up to 2200 again, and I am good to accelerate in third. Or, I can completely let off the gas, then as soon as I press the pedal, it will jump right back to third and I am good. I do not know what the tranny uses to decide when to shift. I would almost say it seems like a TPS giving a bad signal, or maybe something running from vacuum. Also, I dont think it does it when it is cold, only once it is near warm. Sorry for the long post.

Thanks, Robert

gagt Mechanic
12-29-2008, 09:15 PM
could be tps related or you could have a sticking shift silinoid.

12-29-2008, 10:39 PM
ok how about this i have also noticed that on a cold morning, before it gets warmed up at all, I can just barely flick the throttle, i mean just a real fast light jab, and it will bog down from like 1100 to 800 it only sucks air, and does not compensate with gas.. Maybe this too can be a symptom of my (bad) TPS?

thanks for the input robert

P.S, what is the easy fix for the solenoid

gagt Mechanic
12-29-2008, 11:45 PM
lack of power when cold is some what normal. col air is denser and you car is running a some what not optimum fuel trim until your car is at operrating temp.
not to big into transes, but basic a/t is you have two shift solenoids, there is 4 different combinations that can be made from opening and closing them. (oc,co,cc,oo)each each combination represents a gear, so based off this generic exp, if oc was first gear but shift solenoid 1 was stuck open, when it tried to shift to second, or co, it would go to fourth/lock up oo since sol 1 is always open. now you would need a scanner to moniter solenoid operation.