2008 Aveo Power Loss someone please help me

[bklaughlin]

I need help my car has been in and out of the shop, nobody can figure this out. I will be driving the car and while pressing on the gas the car will lose power not die or sputter. just no power. If I pullover turn the car off and restart it the car is fine for a while. Also my gas mileage has drastically reduced. I have just recently had to have the cadilytic converter replace under warranty, fuel pump and 2 injectors. The car start all this at 45K and I am at 56K on mileage now. Can anyone give me any insight, The check engine light is on and the codes read out oxygen sensor, fuel pump, ect. All have been replaced to unclude the fuel pump twice. The car does start to idle roughly and starts missing right before this power loss occurs.

[Z34guy]

check your transmission fluid. That would be my first guess.

[bklaughlin]

all fluid levels are normal and pressure checks have come back normal

[petrified.rabbit]

what do the rpm's do during this? do they go up with the pedal or stay flat? is throttle response an issue?

do you have any codes?

If you have a flat unresponsive rpm, its either the pedal or the throttle body and your drive by wire is keeping the rpm the same not sensing the change.

Otherwise it might be your map sensor not feeling the change in "demand" to accelerate the the engine.


but it depends on what you mean by no power.. if the car is sticking in a high gear, it will have no power, and shutting it off with reset whatever is wrong.. possibly computer?

[bklaughlin]

The rpms stay the same, I do not know what you mean by throttle response, I was getting a code but the code is the misfire, 02 sensor, fuel pump, code which according to the mechanic said that if the car is missing at all it is always going to throw that code.

easy way to explain, I will be driving down the freeway at 65 to 70 and I can start to feel the car miss just the slight hesitation even though i may have it on cruise control or just even steady gas and all of a sudden i will start to lose power. my cars speed decreases like I am not pressing on the gas even though I am. As long as I pull over shut the car off and restart it the car acts as though it never happened and I can drive on. It happens more when the gas tank is at a lower level than it does on a full tank of gas and I have also lost about 40-50 miles in gas milage per tank of gas due to this issue.

[Ratchet104]

The exact codes you have would help drastically...but sounds like an electrical problem

[petrified.rabbit]

Does this happen "every" time you drive it on the highway? After about 20 minutes or so? And then you have to let it sit for 2-3 minutes before restarting it and it runs fine for how long?

Its sounds like the fuel pump but since you replaced that, i have more questions. Does the car respond to you giving more gas with a bogging sound? (like giving the pedal a push makes you lose power faster?) You can get a misfire code AND an o2 code when the engine is trying to run without gas in it. So you mechanic is half right. Not sure how you came up with replacing the cat, that typically happens with a misfire and fuel going into the exhaust. Did he tell you it was clogged? That you mean you had fuel.

The numbers for the codes would certainly help, but just from what you say it does, and what codes you have, and what you have replaced. (As its always a guess when your "fixing" a car over the internet) I am going to say its possibly the fuel pump relay. Have you replaced that yet? The fact it happens at a low tank, means the fuel pump is hotter drawing more, which in turn the heat in the wiring (which is normal your not going to catch on fire) can overheat a bad fuel pump relay. Shutting the fuel pump off and creating a condition very similar to what you describe.

[bklaughlin]

Ok so I had my ECU reset for the mechanic who has been troubleshootin my car. 7 codes came up, he went to a chevy mechanic and 1 of the codes was an alert to chevydealers and mechanics about the ECU UNITS. One of the coded says I have a bad ECu unit and the other one could either be a mis read because the ECU unit is going out or legit but know way to know until I replace the ECU unit. So I have purchased a used one with 15K miles on it and a 1 year warranty. Queston is how do I install this and is there something that has t be done after the install.