1999 Blazer start and ecceleration problem

I suspect the spider injection assembly is leaking. To verify do a fuel pressure bleed down test. Fuel pressure should show 56 to 63 lbs. and once fuel pressure is built up on the fuel pressure gauge, with the key in the off position, watch the fuel pressure gauge. Pressure should not drop more than 5 lbs. in 3 minutes. Hard starting also can be the result of a fuel pump going bad. Make sure the fuel pressure falls within range.

mechanic checked fuel pressure and its excellent

Thank you TrannyMan, then this guy has his answers. I did mention checking for injector pulse also. But his question says hard starting which has to do with a problem with spider injection.

would the fuel bar seal, or pressure control cause the problem? Can anything else cause it?

the fuel regulator was totally no good, and just fell apart on removal. Both the O2 sensors also weren't working for quite awhile.

Was a pressure bleed down test done? Fuel pressure would show good with a new fuel pump. 1996 to 2000 spider injection assemblies are know to have a problem, and since ben redesigned. The original spider injection assemblies leaked. Common problem.

The fuel pressure is steady between 50 and 60

50 lbs is too low, it must be up at least 56 lbs. This is why it is hard starting. So you don't know if the guy did a fuel pressure bleed down test.

I think he just checked it starting, and running

You know, it is not hard to do, the fuel pressure gauge just snaps onto the Schrader Valve. You can rent a fuel pressure gauge from the parts store and have them have it set up for a Schrader Valve, and check it your self. In trying to repair the spider injection assembly, like the fuel regulator being changed out or replacing a leaking injector, the repair may last 6 months if your lucky. It is recommended to replace the spider assembly if you plan on keeping the vehicle. Also it is just as much work to repair as it is to just replace the assembly.

Okay thanks for the advice guys. Much appreciated. I will do a standing pressure check and go from there.