Lurching & hard to start

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1991 GMC SIERRA
4WD

I have a 1991 gmc z71 4x4 sierra 1500 efi. Recently the truck started lurching, became hard to start & quite often won't atart for 30-60 minutes after shutting it off. My son checked his school books from nascar tech which says the problem is egr related, so I replaced the egr & the egr solenoid but no luck. Any help would be greatly appreciated.

1 Reply

RASMATAZ

MECHANIC
75,992 POSTS

Next time it refuses to start don't wait for it to make up its mind-do below immediately to determine if its fuel or spark problem

https://www.2carpros.com/articles/car-cranks-but-wont-start

Get a helper disconnect a sparkplug wire or 2 and ground it to the engine atleast 3/16 away from ground-have helper crank engine over-do you have a snapping blue spark? If so-you have a fuel related problem, Do you hear the fuel pump come On when you turn key on? If not check fuel pump fuse and fuel pump relay if okay-check the fuel pressure to rule out the fuel filter/fuel pump/pressure regulator and listen to the injector/s are they pulsing or hook up a noid light. No snapping blue spark continue to troubleshoot the ignition system-power input to the coil/coil packs,coil's resistances,cap and rotor,distributor pick-up coil, ignition control module, cam and crank sensors and computer Note: If it doesn't apply disregard it and keep testing