94 Ls400 Problems Please Help

[lexfourcam]

my car has been acting up the whole intake where the vacuum lines are has been replaced the car is acting funny the wheel doesn't come down ne more and the car won't run for long before it cuts off and the rpm goes crazy and will rev from 600 down to 100 then rev over a 1000 its not driveable and it shuts off sometimes i think it could be the alternator but im not sure the lights get dimmer when the car stops running too please help me out if you can thanks.

[landar]

Lights dimming(slightly) when the engine stops is normal and doesnt necessarily mean you have a bad alternator.

Sounds like gremlins have taken up residence in your Lex. I would find the nearest priest :whistles:

Seriously, this could be an electrical problem with the computer, a bad sensor, bad connection, etc. With the engine acting this erratically,

do you have a check engine light coming on and/or codes you can pull? Mileage and maintanence history on the car, please?

Depending on the history, could be time for an old-fashioned tune-up to begin with.

[lexfourcam]

Lights dimming(slightly) when the engine stops is normal and doesnt necessarily mean you have a bad alternator.

Sounds like gremlins have taken up residence in your Lex. I would find the nearest priest :whistles:

Seriously, this could be an electrical problem with the computer, a bad sensor, bad connection, etc. With the engine acting this erratically,

do you have a check engine light coming on and/or codes you can pull? Mileage and maintanence history on the car, please?

Depending on the history, could be time for an old-fashioned tune-up to begin with.

ok well i bought the car from a dealership and it was running fine then nothing wrong with it i got the oil changed not so long ago maybe 500 miles and i got a vacuum fixed and then this *BLEEP* happens they pulled the engine code and they said it was mass air flow but ive looked at it and its as clean as can be and its brand new too but i agree with you i think it quite possibly is the alternator

[Jerry Bransford]

Unless the battery is bad/drained, the alternator won't cause this issue. So long as the battery has a charge on it, the engine will run fine... until the battery goes bad. But if the engine starts normally, you can be assured that's not the issue.

I'd start looking for another source of a vacuum leak. Spraying the various vacuum lines, vacuum manifolds, and vacuum connectors with an aerosol carb or throttle body cleaner will help you find any possible leaks in the vacuum system. The engine RPMs will suddenly change as the cleaner finds its way into the engine as it gets sucked in through any leak it gets sprayed onto.