2002 Malibu

[Harmonator]

2002 Chevy Malibu

106000 miles

When driving with the cruise control on going up a hill the engine pulse, meaning the RPM's fluctuate up and down. It is almost like the tranny does not allow it to downshift. If I get on the gas all is well. I know its not much of description but I seem to have a hard time trying to explain it.

Thanks in advance.

[SStracker]

Im sister had a 2001 malibu that did the same type of thing you are describing. She took it in under warrenty and they test drove it and said nothing was wrong. She ended up selling it to a friend when she got a new audi and i know that the tranny just took a dump on her friend with about 99*** miles on it. Sorry im not more help but im thinking after about 100,000 miles the tranny starts to go. good luck

[Shack]

Harm,

Any check eng. lights come on?

Have you flushed the trans in the last 30,000-40,000 miles?

Did this just started?

[Jeremy airjer W]

how many rpms are we talking?

If you can drive down a straight stretch of highway. Using your right foot to maintain a steady cruise push down on the brake pedal with your left foot just enough to turn on the brake lights but not enough for the brakes to slow you down. You should notice an increase in rpm. When you let of the brake the RPM should go down. If it does this is it the same rpm difference that you have when you have the cruise set?

[FlatBottom]

I'm having the same issue with my 2000 Malibu (108000 miles). It's still running good, it only seems to happen when I have cruise on also. I wasn't going to let it bother me to much, but now...seeing guys with similar years similar miles...HMMMM

[Harmonator]

Thanks for the replies. Yes this just started and yes the check engine light came on when this occurred. After the first time this happened I had the oil changed and the check eng light checked. The computer told my machanic that it was a oil pressure code, but he was confused. I bought the vehicle with 55K on it so if the previous owner did not flush tranny it has not been done. RPM's are normal 60mph @ 16 to 1800, when this occurs it will go from 15 to 2200.

[Jeremy airjer W]

The check engine light is a good start. It would be helpful to find out what code(s) are present.

[Scott K]

Diagnosing the check engine light would be a good start. I have seen on other model vehicles where the Mass air flow sensor, or egr valve coming on when it isnt suppose to, cause concerns like this. You could pull the vacuum hose off the egr valve and redrive it to see if it still happens. Or check the MAF.

[Jeremy airjer W]

Its an electrically controlled EGR valve there will not be a vacuum hose.

[Harmonator]

I sure appreciate the replies. It looks like I will have to go and have it plugged in. I will update you guys on the diagnosis.

Thanks again,

Tom

[Jeremy airjer W]

I think that would be the best option. At least we will have a better idea of what direction to steer you in.

[Harmonator]

Well, I finally got around to getting the car in. The computer gave a bogus code so my mechanic took the car for a spin. He noticed that it cranked over more than what should be normal before starting and questioned it. Well long story short my fuel pump was not producing the right amount pressure. When the gas tank was hit with a rubber hammer it was normal, shut the car off and restart and it was very low. Some $$$$$ later and now all is well.

Thanks for the input

[Jeremy airjer W]

I wouldn't have thought that would be it!

Thanks for the fix!!