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Jared D
Jared D, ASE Certified Technician
Category: GM
Satisfied Customers: 1906
Experience:  Shop Supervisor at County Fleet
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I have a chevy 4.3 ltr that the timing goes in and out back

Customer Question

I have a chevy 4.3 ltr that the timing goes in and out back and forth with the engine idling with said movements sometimes it goes out so far the truck stalls and wont start back for a couple of hours until what ever sensor fixes itself what causes this and what do i need to replace?
Submitted: 2 years ago.
Category: GM
Expert:  Jared D replied 2 years ago.

What year model is the truck? Some of the late model Chevy trucks have temperature sensors that adjust the timing electronically based on the engine temp. If one of those sensors is faulty it could cause the condition you are describing. When you say the timing is off, have you checked it with a timing light, or scope? How many degrees off is it? Advanced or retarded?

Or are you referring to the idle when you say timing?

Customer: replied 2 years ago.
The truck is a 91 model when i say the timing is off i mean it moves back and forth all over the ricktor scale i think it is advancing but it may be retarding when i check it with the light the dash moves to the left looking at the front of the truck
Expert:  Jared D replied 2 years ago.

The timing mark on the crank moved to the left of the indicator? That's usually retarding the timing. I would think there is something wrong in the distributor of it isn't affected by engine temperature. There are weights and springs in the distributor that advance the timing as centripetal force increases. Those springs are probably worn out. Any other symptoms? Noise, smoking, etc.

Customer: replied 2 years ago.
Its not affected by temperature it can do it anytime but normally when it is warm, no other symptoms just random timing issue so should I replace the distributer and see if that fixes it?
Expert:  Jared D replied 2 years ago.

I think that's your safest bet. It's not the cheapest, but there is very little else that affects the timing on this model.