I recently purchased a 1989 Chevy K1500, and when I initially start it, it cranks for 10-15 seconds before starting to fire up no matter the temp outside and when idling to warm up , the idle will fall really low and surge back up around 5-10 times before stalling completely, and it does it occasionally when it is hot, as well as stalling after any relatively hard take off, and it has very little get-up-and-go plus it takes another 10-15 seconds of cranking after it stalls to start back up. Previous owner did have a clear hose on the IP so I could see that it had an air leak, I replaced that line with another clear hose and it started running better with no air leaks but after sitting over night the air leak came back, so I replaced that hose with a black fuel hose and it ran good again until this morning when it acted the same or maybe a little worse at idle and now it does it more when it is hot. Any ideas on what it could be? I´m at a loss, I am thinking fuel filter may be clogged but that does not explain the air bubbles, and this is my first diesel, my Dad is encouraging me to sell it and buy a gasser, but I really like this truck so far, even with its issues. However, I am on the edge of selling it at this point cause its starting to p*ss me off that it won´t idle long enough for me to safely drive and not ruin the engine!

 

Well here goes.... Ya might have to trace and REALLY inspect the fuel line(S), from end to end, all connections. Something is definitely amiss. Sounds like losing its prime. Have you noticed any puddles under your rig? A good inspection may reveal wetness maybe at a junction or worn spot on the fuel line caused my vibration. replace all rubber section(s) with good quality rubber hose and clamps. really look at the IP for wetness, drip leaks or puddle(s). Could also be a failing injector.

 

Wondering if you resolved this issue?