Getting frustrated..I have a 2000 4x4. Problem I'm having is that when the truck is in park and I rev it from idle to redline almost no hesitation. When I drive and go wot a little hesitation. If I'm light footed after it shifts it seems to hesitate a lot until about 2500-3000 rpms. I have changed plugs, plug wires, cap/rotor, fuel filter, pcv valve, and coil. I have cleaned the egr valve. I cleaned the maf sensor, and even bought one from the junk yard to rule out the maf sensor being bad so I didn't spend $100 on a new one if it wasn't the problem. Idles smooth, no jumping around. Stays consistent on hills. Some help would be appreciated. Thanks in advance

 

without seeing the problem, might be a clogged catalytic converter. i had a old 85 s10 like that, it would rev no problem but try to accelerate and it felt like i was pulling a trailer. one little trick i do is if you have a welder, drill like 5 1/4 inch holes on the exhaust pipe at a easily accessible place before the converter and redrive it. if it picks up power your cat is clogged. if it doesnt fix it you can easily re-weld the holes up

 

we've had the blazer a year and a half..had to had a couple exhaust leaks fixed and they said that the cat had been changed..they said it has a bigger cat than stock..i think its a walker. Everything after the cat is original piping. I re changed the cap/rotor and that seemed to help a lot. When I replaced it 8 months ago, I replaced it with a master pro set, which is oriellys house brand..this time I put ac delco cap/rotor and it definitely picked it up.