I have a Malibu MAXX LS. For some reason after the engine had been started within a four hour window, the car will not restart unless the accelator is pushed/pumped. Also, the car does not idle smoothly. This does not happen when the car has been off overnight or during a long period of no use. Any ideas?

 

Dirty throttle body possibly. Since it runs when cold when the TB is open more.

 

Dirty Fuel Filter

 

Both are good suggestions. I would also try some fuel cleaner to help flush the injectors.

 

I second all sugestions posted above

 

The fuel filter is in the tank, a supposedly self cleaning sock.

 

Ok, how do I clean either the fuel filter or the throttle body?

 

Well assuming it's not a electronic throttle body; you can use brake clean or lacquer thinner. I prefer lacquer thinner. Take the TPS and the IAC valve off of the Tb. Get a paint brush and use the lacquer thinner to clean the TB thuroughly. Then clean the IAC valve. Keep the piston pointing downward so the cleaning agent doesn't go back inside the valve and mess it up. You are cleaning all of the black gunk out of there. That is carbon. It will come off relatively easy.

Do Not Try To Clean The TPS. You will mess it up completely. Get a new throttle body gasket from Chevy and then bolt the TB back up. Do not get any of the Lacquer thinner near the connectors of anything. Lacquer thinner can be purchased at advanved auto or something similar.

As for the fuel filter it will have to be replaced. I would try using fuel cleaner first. Try using BG 44K. If that and the TB cleaning doesn't work then I would replace it.

 

I use TB spray cleaner and a tooth brush. Your TB valve is most likely just gunked up if this is the problem.

 

I would ONLY use throttle body cleaner to clean the parts. no worries of ruining parts and if you happen to get some in th throttle body, there is no worry of ruining your o2 sensors or the converter for that matter