Sorry for asking this question again but I thought I had fixed it and it came back. So I have a '97 Blazer 4x4 and I am having a hesitation problem with it, usually when it shifts from 1st to 2nd. It is not as bad now as it was when I bought it. I changed out the plugs wires cap and rotor and it went away completely and I thought I was done with it, but it turns out I was wrong because it came back about a month later. Just to name the things I've had done on it: fuel filter, fuel pump, air filter, had the injectors professionally cleaned, new gaskets on the valve covers and intake, flushed and replaced the tranny fluid with a new filter and gasket, and of course the oil with AC Delco filter. This also usually occurs on chillier, damper days. Can anyone help me with this?

 

If it completely went away after you changed the plugs, cap, and rotor, I would look there first. check the plugs, maybe they are fouling, and it just took a month for the new ones to foul up? This, along with happening on damper days seems like ignition related to me.

 

I had a similar issue and it turned out my timing was really off, I'd say take it to a shop and get your timing checked.

 

Verify no vacuum leaks and TPS voltage test as well. Both those can cause shifting problems.

 

Did you re-install the hose on the back of the air intake? I keep forgetting that one, it runs fine, but hesitates at lower RPM.

 

Checked out the plugs wires cap and rotor and they are fine. Everything is hooked up and there are no vaccum leaks as far as I know. I'm starting to think maybe it's a tranny problem...it has 240K miles on it after all