Strange problem - lack of power 30 seconds after startup

My truck is a 1998 3/4 ton Chevy crew cab short bed, with 5.7 engine, 4x4. I have new plugs, wires, cap, rotor, and air filter. No major repairs ever. 140,000 miles. Problem same vehicle hot or cold.


30 seconds to 1 minute after I start up the truck when I try to accelerate, it bogs down significantly, it can barely keep going, let alone accelerate. After about 15-25 seconds, it goes away, and I can drive and accelerate like normal. It feels almost like the truck is not getting enought gas.

IF I push the pedal way down when it has this problem, it will sputter and pop significantly, the problem lasts longer. It goes away more quickly if I let off the gas and slowly, barely give gas.

The problem was exactly the same before and after fuel pump replacement. Has been happening since 50,000 miles. Seems like it's getting a bit worse, but can't be sure.

Any ideas? It feels like it's just not getting any fuel during that startup drive. If I sit in the parking lot for 2 mins, then go, It does not do it.

My 1st thought is the CTS (Coolant Temp Sensor). Need to get an engine capable scanner on it and see what it's reading. Any codes stored to help us out??

My 1st thought is the CTS (Coolant Temp Sensor). Need to get an engine capable scanner on it and see what it's reading. Any codes stored to help us out??

Nope, it is not throwing any codes at all.

Do you think the Coolant would warm up enough in those 30 seconds to make the difference with the sensor?

What is the fuel pressure at startup and for 30 seconds after startup?

//2000CAYukon