1987 Suburban Idle Issues

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GTP51

Full Access Member
Joined
Sep 6, 2017
Posts
112
Reaction score
124
Location
Melbourne Australia
First Name
Geoff
Truck Year
1987
Truck Model
R10 Silverado half ton Stepside
Engine Size
355
Having been down this rabbit hole before and pretty much followed the pattern you did, I ended up finding the throttle shaft bushings were worn and allowing air to bypass, and it did not show up when chasing Vac leaks, I replaced the TBI unit with one of the modified ones that you see on Ebay worked a treat and even picked up a few HP.
Have since gone to a Holley Sniper set up and have the TBI unit sitting in a box on the shelf.
 

Smokenbones

Junior Member
Joined
Nov 5, 2021
Posts
1
Reaction score
0
Location
Arkansas
First Name
Kenneth
Truck Year
82
Truck Model
C10
Engine Size
305
Have you tried cracking the gas cap to release the pressure before trying to start it. Not sure if the cap is supposed to be vented or not but have had them to fail.
 

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