2002 chevy trailblazer stall and oil light

When I stop at red light oil pressure gauge drops to zero and then back up and engine tries to stall. Then i take off and its fine, it only happens driving in town,not on interstate. Any help?

Answer: The light is coming on because it is nearing a stall. The stalling is the main problem.

Check fuel pressure, carbon in the throttle, scan the computer for codes.

Chevy Trailblazer Won’t start Sometimes

I can get in and try to start the truck, sometimes it will start and some times it won’t. When it won’t start, all the lights come on and no crank. If I wait a while and try again, it may start.
I have already changed the ignition switch and that was not the problem. Any Ideas?

Answer: There are two common causes for your Trailblazer with the 4.2L straight six cylinder engine  to not start sometimes. A faulty “Crank Relay”. In the underhood fuse box is a relay labeled Crank. Either replace it, since they are cheap enough, or swap it out with another one in the fusebox of the same exact type.

The other is that the starter is going bad. From under the truck of through the drivers side front wheel well, you can get a long 1/2 extension. Have try to start the truck until it does not crank, then tap on the extension on the starter with a hammer several times while truing key from off to start to off to start. If it starts to crank or makes other noises, then the starter needs to be replaced.

There are only two 15mm bolts that hold the starter on the engine. Be sure to disconnect the battery before replacing it.