2002 Chevy Zr2 blazer starts rough but when it does start dies when in gear
 

i need help my blazer quit about two weeks ago my mechanic installed a new fuel pump and fuel filter and as soon as I drove away from his shop it started backfiring so I ended up with a lot of o2 sensor faults and 1 multiple misfire code it had just had a tune up before all this happened and it still wouldn't run properly so I put in a new iac valve and that didn't work so I put in an ac delco cap and rotor and all the codes went away now when I get it started which takes awhile it will idol until I put it in gear and then die again but my scanner is throwing no codes I'm a little frustrated and confused can anyone tell me what's going on? I Would appreciate it

Start by testing fuel system per sticky at the top of the 2nd gen forum. Report all four values and we will go from there. Doesn't matter if your fuel pump and filter are new.
1) pressure at Schrader valve
2) leakdown rate at Schrader valve
3) dead ended fuel pressure
4) dead-ended leakdown rate
You can get a loaner (with deposit) fuel pressure gauge from local parts store. The rest of the stuff you will have to buy the fittings and make. Just read the sticky and don't try to short cut it. Know that there is one spec in the sticky that IMHO is wrong. 58 psi is normal for the MPFI spiders (does not require the FPR to give 60 psi).

Ok so it maxes out a 54 psi and once turned off Holds steady at about 49 psi

OK so you have a fuel pressure problem as I suspected, but you can't tell what is causing it. Now what do you do? Read and follow the sticky - then report the four values I asked for in my previous post please.

I appreciate the help but it looks like I was looking in the wrong place the best it had run was when I changed the cap and rotor so I took another look and my rotor does not line up with the distributor itself it's out about 10 degrees looks like it's a timing thing and it looks like I'll have to go to a mechanic as it can only be reset with a professional scanner from what I understand but if not I would love to hear how to reset the distributor