So i go out start the blazer, starts and runs fine. Get in put it in gear, starts chuggin and ******* real bad for the first five minutes, then, usually, clears up, any ideas?? Did all the obvious, plugs, wires, cap and rotar, oil change, tranny service, fuel sys. cleaner. Check engine light not on. Have heard about intake leak problems with these vortec's, checked using starting fluid, havnt found any obvious leaks. Really, really stumped!!! Does this every time it sits for longer than about 20 mins.

 

Did you clean the EGR valve, throttle body (including IAC valve), and the MAF sensor? If not, give those things a try.

 

You say the CE light comes on. What codes?

 

he said the CE light does not come on...

 

Do you or have you had and noise of any kind coming from underneath? An easy way to chech the CAT is to remove the o2 sensors that are between the manifold and cat, crank it up, and excelerate. If you have a loud noise and loud rattling your Cat is stopped up. These CATs are a pain in the *** and most are welded, but you can find a universal that bolts on.

 

Didnt Clean any of those, will try that. No CE Light. I know the cats not pluggled, hollowed it out when i suspected it was plugged before, not the prefered method but a cheap fix.