1998 5.7L Vortec in K1500 137k miles with Silverado package.
The engine has a transient starting problem, sometimes serious. I am in interior of Panama with it (about 2 hrs to Panama City for a dealer and authentic parts).

Once I could not start it at all and had it towed to a local mechanic's shop. Other times I have been able to get it started after 15 - 20 minutes (trying the tricks). It appears that the issue is escalating, so must be serious.

If the engine starts then it works just fine on all reasonable RPM up the steep mountains and on highway. If it does not, then the fuel pump is kicking in for 2 sec initially and must be keeping the pressure up while driving. The one time in the shop after checking few things the mechanic asked me to crank while he opened the fuel line vent under hood. According to him lots of air was in fuel line. After that engine started every time fine for about 2 weeks.

In a recent incident I tried same trick asking a friend to crank while I opened the valve. There was air, but the engine did not start anyway. Luckily I was parked right opposite to a mechanic's shop and I asked for help. The guy came out and bumped the fuel tank couple of times. Engine started fine.

Last time engine did not start I tried same trick, but bumping the tank made no difference. So far I have been able to start it after a while cranking with wide open throttle. To me this indicates flooded plugs. Perhaps something else as well I don't know? When the engine starts like that the idle is rough for 30 - 50 seconds and the engine is very close to shutting off unless I keep throttle open, but stabilizes fast and then runs fine.

It is warm in Panama (around 92+ F). It could be a bad coolant temp sensor, but there are no DTC codes recorded and a bad sensor should affect performance all the times, not only while starting. The engine starts with open loop though even when it is warm.

All help and ideas are highly appreciated. As you understand I am not in position to run around the corner to Advanced... or Autozone and buy this or that to try if it fixes the problem. I have the little gizmo that reads computer real time and displays up to 4 different parameters.
What parameters would help to diagnose?

I do apologize for long story, but few words about history of this truck. I bought it in Feb with 131k miles. Appeared well maintained, but bad breaks. I replaced most of the breaking system, few other suspicious things and drove it down from Florida to Panama without a single problem. It is fed with a local 91 octane gasoline (there is nothing less) and oiled with 20W-50. The oil consumption is minimal (1/2 qrt per 5000 miles), there is no coolant leak nor oil or gasoline leak.

 

I've changed out the fuel injectors (spider) and i checked my feul filter, and checked my fuel pump. But my truck still won't start, can u tell me what else i need to look at?

 

What happened from last time it did start?