Hi I have a 2000 blazer and it developed a bad hesitation around 2000 rpm I changed fuel pump because it broke. Then I changed pcv, fuel filter, cap and rotor, cel went away but I got the codes while it was on. P1870 just ordered valve body rebuild kit with shift kit. To correct the as I see it manufacturer flaw.i hope it fixes this problem. It has a hard time staying in third jumps right to fourth. And it threw codes p0171 and p0174 means it's running lean. Hoping it was injectors and some injector cleaner would help I put that in my tank with premium gas. And changed all parts listed above. But the hesitation didn't go away... check engine light went away but still ran like crap. I just unplugged the maf sensor and it ran better no hesitations. So I cleaned it with maf sensor cleaner plugged it in and ran like crap still.. tomorrow after it sits at work I'm gonna try spraying vacuum lines see if I got a vacuum leak I ordered intake manifold gasket kit hoping I don't have to go that far and return it... any suggestions?

 

Could the code be thrown by bad spark plugs and wires?

 

Checked all vacuum hoses and it was a torn vacuum hose... ran around town trying to find one everyone seemed to have had the same problem today and everyone ran out of hoses. But I found what I needed put it on fired it up and bam light went away. But my 4l60e transmission still has a shifting problem. So next I'm rebuilding valve body and putting in shift kit with new filter fluids and gasket.