My 88 Silverado 350 with about 400k miles wouldn't start without priming the throttle body. Initially, I thought it was out of gas. The gauge hasn't worked properly since I've owned it.
I put 7 gallons in the tank, primed the throttle body and started it up. It ran normally, but after sitting for a minute it wouldn't start again without a prime.
I can get a pretty good look at the spray pattern with an LED flashlight, and the first few times it dripped a few tiny drips of fuel from the injectors when trying to start, but now I don't see any fuel when cranking.
Now, before I go on, the fuel pump is still working.
I can hear the pump cycling like normal, and after I prime it it runs normally. It's not starved for fuel at a higher demand level; it will pull at full throttle all the way to the shift point.
The spray pattern from the injectors looks normal when it's running.
I changed the fuel filter yesterday morning, primed it afterwards, and it started and ran normally with the prime (just like it has since this started). It then restarted fine after I finished cleaning up.
I tried it again last night after about 6 hours and it fired right up. I figured, problem solved, especially when it again started this morning like normal.
Feeling confident, I drove the truck to work, then when I got ready to come home, no start. Naturally, I had been in a rush, and didn't bring any gas to prime it. My wife had to drive the 18 miles from home to bring me a can of gas. Not a win, but to her credit, no complaints.
So, the fuel filter made a big difference but the problem still persists. I'm thinking the next step is to check out the fuel pressure regulator.
Any comments or suggestions?