My 1989 chevy c1500 will try to start but will keep dying. after a while it will start back up and may die and may not. happens more and more often. sometimes just driving down the street. someone said it is the brain. just put new fuel pump and o2 sensor on it, battery is new too.

A common problem on these trucks with the symtoms you described is the gasket under the throttle body. It's about a $2 part. Ther's only three bolts that hold the throttle body on. You can leave everything attached to it and just lift it up about a quarter inch, slide the old gasket out, slide the new one in. It's worth a try.

i would look at starter fusable links all lights are powered through there might be touching metal if soft rubber is worn through

check the connection on the starter but make sure it has oil in the motor and its not locke up

Sounds like a poor idle. try adjusting the idle screw.

don't know for sure but my 98 had simmilar problems and it ended up being the ignition switch,not the key switch but the actual ign switch.worth a try.

Check the electrical for key on power to the fuel pump relay, it sounds like the pump will only run in the start position.

removed the dis cap then try to rotate the belt thuse turning belt see if there is any slack when rotor turns if there is slack or even slight hesitation while turning u need a timing chain & gear

You might have some blown head gaskets..Hope none got in to the engine oil and filled it up with water..Check oil for coolant and spark plugs for coolant also.Another place to check is the exhaust pipe.Make sure none was running in to there

I’m happy to assist further over the phone at https://www.6ya.com/expert/joe_a3369546f8067589

Have you Checked the Fuel Filter? Not sure what Model But, The C1500 Fuel Filter is Underneath and Inside of the Frame Rail on the Passenger Side. Check That and Message Back!

Hi lanzmick,

A few questions:

• Is it difficult to start too? Need to keep your foot on the pedal?
• Carb or FI?
• Did this just start happening? Gradually? Correspond with some other event or part replacement?
• I believe your vehicle has an option for OBDII diagnostics. If so, stop by an auto parts store and ask if they can do a code reading. Most will do it at no cost. This will hopefully give a definitive reason for the problems.
  

In the meantime, check for vacuum leaks. Inspect for loose or cracked hoses.
I know this can be difficult, but try keeping it running while listening for a sucking sound that isn't the intake.

If it's carb'ed, check the choke and its associated linkages.

Check the timing.

Get back to me with the results, we can pick up from there.
Mike