99 4.3 4x4 200,000 miles had plugs ,wires ,cap rotor etc in the last 6 months. my sister called and said it was sucking gas down and running bad. i picked it up checked and found a few miss fire codes . i checked and found the spider injector was bad I got a new one and when i took upper intake off #6 was pissing out and also had a small puddle by the #3. I installed the new one (aftermarket Rebuilt) started vehicle and it ran for 30 seconds then died the next time i cranked it had an extreme backfire I pulled upper manifold off and i got a bad reman so I took it back got another and after i put this one in it wants to start but wont. there is a new map sensor it has 60 lbs of fuel pressure. it has good spark. could the backfire have killed the mass air flow so i get the no start? im an old tech that needs a hand can anyone please respond. i have alot of relatives and work on most of there cars this one got me

 

you check the compression?? could it have jumped time?? I have an 01 4.3 Im having issues with but seems to make no difference if the MAF is pugged in or not, mine will start only when cold and when it warms up it dies..im still figuring this motor out as the Crank Pos sensor and the Cam Pos sensor both help time the motor from what I have read. I hope this helps