I have a 97 Cav. z24 and i am having the same problems...sometimes when i first start it up and start to go then it starts spittin and sputterin and running like crap will about 5 secs if it hasnt died then it will fix itself and runs fine..im currently in a diesel/auto mech course so i hooked it up to the scanner to see if any codes have coded for it and what i found was that the anti-theft for the fuel was reading incorrect which was making the ecm overtemp in return causing random missfire....so this one problem is coding 3 different codes...so right now im trying to research to figure a way to over ride or turn off the anti-theft to see if it will fix the problem...this is the only senseable solution since ive read that others have change every mech. piece known to man....which figures it would have to deal with the stupid computer....so if i figure it out or if someone else please post a reply