Caasim

My friend drives a '95 Lexus LS 400, and he's been having a problem lately.

Whenever he stops at stop lights, his car will sometimes shut off. The car is automatic, so it's not him stalling out the car.

Anyone know what it could be?

DisturbedFocus

I would start with the maf and the ecu and work back from there

F4Fresh

Maf Sensor. Clean it.

Fabrik8

And replace the air filter, it probably needs it. Make sure the plugs and wires (if applicable) are good too, I'm assuming that engine probably has coil packs so the plugs are probably the only thing. Any drivability problems, hesitation, loss of power, anything like that? Does that engine have a pair of throttle bodies?

Reset the ECU also. Chances are if the MAF is fine, there is a probably a sensor going bad. MAFs don't last forever, so that may need replacing. Make sure to go through the troubleshooting process first though, because those bitches aren't cheap.

minnis4g63

i would try the idle air control valve first its the only thing that really controls the idle of the vehicle a lexus can actually run wiithout the maf hooked up it just runs very poorly like its onlt on two plugs. the only reason i know this is because my moms i left it unhooked when we changed her intake out

Fabrik8

ECUs have default (fixed) parameters that they use when they detect a sensor fault, so when you unplug the MAF the default parameter isn't necessarily very close to what it should be at that load/RPM ordinate, so it runs like shit. Simple.

pasty

Good info!^^^

I recently had a problem with my MAF sensor where one of the internal leads managed to break loose from the solder point and caused a bunch of trouble. If it would start up it would die, and if by some chance it didn't die it would go into limp home mode.