I have a 1999 4x4 blazer. For a while now it has been lacking power. By that I mean when you 'give it gas' it studders, or hesitates. It doesn't happen all the time, although it does happen a few times a day - which is a few times too many. It's actually dangerous at intersections because sometimes it just doesn't move when I need it to, and I never know when it's going to happen. I took it to a local Chevy dealer to get this problem fixed and after over 2 weeks, they called to tell me they absolutely could not figure it out. They changed the fuel pump and filters, checked injectors, changed cam sensor, made the distrubutor adjustable and adjusted it, checked timing, put in a new computer, and other things. I was amazed to hear that THEY couldn't even figure it out so now you are my last hope. :- ) Please - any ideas?
Thanks.

 

Is the engine reving up and not going anywhere?

 

Might be the torque converter and not the engine. To follow up on thegr81's comment, watch your RPM's. Easy to mistake the engine having problems when your tc starts acting up.

 

Thanks, I'll look next time it happens but I don't think the engine revs up, and rpms dont rise either. My simple way of describing it is sometimes when I hit the pedal, it just doesnt move, it bogs down and has no power. Mechanics said it acts like it doesnt get enough fuel, but they checked everything. They also said it feels like a transmission slip, but it isn't anything to do with the tranny.

 

I would recommend you clean the MAF sensor (run a search). Do you have a K&N filter installed? If so, the oil will accelerate the collection of dirt on the MAF elements. Even if you do not have a K&N, the MAF can get dirty and hinder it's performance.

Another thing to check would be that the passenger side valve cover vent, that goes into the intake ductwork behind the throttle body, is connected.

 

Take swartlkk advice and also on top of that just make sure everything is cleaned. Now if the mechanic checked everything what is your fuel pressure at??? Also when you start it up what does it sound like i.e. rough, missing etc.??? Still trying to collect as much info from you to diagnose this problem??? One other thing is you maf plugged in???