2000 Malibu LS loses power after warming up
 

Help! This is driving me CRAZY! I just bought a 2000 Malibu LS with 83K. It was owned by an older lady and sat a lot. I noticed that after the car warms up, it performs badly. Lack of power, no pickup, surgiing, hesitation, loss of power on inclines and hills, no power when moving out into traffic from a stop. I brought it to the dealership and they tested the engine and tranny....no problems at all. They think maybe it is moisture or carbon build up. They sprayed some stuff in the intake to get rid of the carbon, and I have been using bottles of dry gas. No improvement, not yet anyway. Why does this happen only after it is warmed up? Any ideas on what could be causing it? Thanks! Also, it may be effecting the gas mileage...it is terrible.

Also, the spark plugs and fuel filter have been changed!

Try cleaning the MAF sensor. Bad gas would run crappy all the time.

Everytime my '00 Malibu starts to loose power I usually find a cracked vacuum hose that causes the engine to stay in "cold" mode which uses more fuel.

Is it easy for you to explain where the MAF sensor is?

Also, I just now checked what hoses I could see from under the hood, and everything looked fine. Should I check from underneath the car, too? (Sorry, I only know a certain amount about cars).

It is in the air intake should have a soft rubber boot on each side with a plug in. Unscrew the two clamps that hold it in the inlet, remove, and use a MAF cleaner (mass air flow sensor). Also as suggested check for vacuum leaks. In your case, I'd suggest get a can of WD-40, with it running, spot spray vacuum hose, and connections. If the engine speeds up, it is sucking air at that point.

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This is the cleaner I use

I'm wondering, since you have this isssue with "warm" engine. If you don't have any luck with the previous, let it warm up, and with wd-40 spot spray the intake. Thats the metal piece on top the engine where the MAF hose goes into. Hit the area where it bolts to the engine. It could be a gasket leak when warm.

kevinkpk...thanks big time! I'm going to work on that tomorrow. I can see the intake and where the MAF should be, as you described. Thanks and I look forward to fixing this annoying problem!