86 blazer 2.8,tries to die when put in gear

Rough idle smoothes out at higher r.p.m. 1000+ lack of power,stalls when put into gear timming's good throttle body's good what could cause this im lost



?confused?

Welcome to Automotive Forums.

You've got a vaccum leak somewhere.
Most people spray WD40 on the vaccum hoses and what not. When the motor rev's then you've just sprayed the leak

After checking for a vacuum leak, if you don't find any, you may want to take a screw driver and tap the MAF sensor with the handle of the screw driver, listen to engine while tapping, if it ildes up and down or just smoothes out, That could be your problem. The fact that it's an 86, you may have both problem. I would check both of them.

also check the HEI module it controles timing advance at lower RPMs and switches off to the ECM at higher RPMs.