ok put a new fuel pump almost 2 months back. runnings goods. but it has started a wierd habit of dieing when i let off the throttle. then it doesn't want to start back up (like its not getting fuel. if i keep trying to start it it'll eventually start up. it may die after a couple of seconds or not. If it sits for a while it'll start back up first or second try. this has gotten progressively worse happening once in a 3 week time to now its an all day battle i replaced a couple of vacuum lines running to the rear area of the intake they where in very rough shape. I'm going to start pulling the throttle body off and clean it. anyway it never dies when you have pressure on the throttle. I think its a vaccum line issue. that old hose may have clogged up the fuel pressure regulator. any other ideas? i'm going to put the pressure gauge to it right now.

 

If you haven't changed the fuel filter, do so. The old pump may have gunked it up with debris from the brushes as they wore. The EGR and IAC (idle air control) valves might need cleaning also. Might check the PCV valve, too.

 

I just posted something on this because mine was doing the same thing I just replaced the spider and it has been running fine everyone told me to check the fuel pump also that wasnt the problem when the guy fixed it he said the spider is the biggest problem with these and everyone goes to fuel pump first and it ends up being the spider

 

...and this post explains how to determine which is causing the problem.

 

along with changing the spider change the spark plugs. when u have repeatedly tried to start the car ,the plugs get overwhelmed with fuel. chances r that the plugs are fouled. all plugs r easy to replace except for one. the second one in on the right if u r looking at the engine. to change this on u have to take the steering rod out of the way. one bolt at the end will release the bar then pry it off. but b4 u do this make sure u lock he steering wheel in place. or u will mess something up, i forgot exactly what but trust me u will. any problems let me know.i just changed mine and it went very smooth and easy. unfortunately it only worked for a couple of days as i bought a used one and it was bad so i have to do it again. but the whole job plugs in all is only and hour at the most. without plugs only 20 min job. but plz do yor self a favor and change the plugs.

 

Before you go disconnecting the steering, try to remove the spark plug using conventional means.

 

To title your post 'definitely the spider' is making a big assumption without knowing the fuel pressure readings. It may be the spider or not. Throwing parts at a problem can be a very expensive way to solve it. At this point I think we should wait and see if the OP reports back with more information.

 

I got up this morning and started the blazer, it started right up i turned it off and drove to part store to get some teflon tape. when i pulled in to the part store it died. I tested the fuel pressure tihe the fuel pressure tester. it was reading around 25 psi or so. After I cranked it a few times the pressure slowly rose and when it hit about 55psi it started. i watched the pressure guage and was would lose about 3 psi when i hit the throttle but would get back to 55psi. So i drove home and it died on the highway thankfully i was able to coast in to the gas station. the pressure was reading low 20's but after a while was making its way up to 45 but the the battery died. I'm sure it'll start up and drive when i get down there with some cables. I'm going to get a pressure regulator today also. I know i'm not sure what the problem is exactly but it seems like its the regulator. any other ideas?

 

You really need to follow the steps listed in the link above and report back with the figures. Don't assume the pump is working correctly just because it's only about 2 months old. We've seen them fail before in that short of a time. As I said, it very could be the FPR, but without the numbers nobody can be sure.
The basic procedure is to hook the gauge, turn the key to 'on', not 'start', and check the numbers. Turn off the key and watch the pressure. It should not drop more than ~ 3-5psi. If it continues to drop over the next 10 minutes, then it is most likely the FPR.

 

i forgot to mention that i can not use the diagnostic computer. I bought this from my brother and he had someone do some programing with their laptop. So the little hand helds don't work. anyway I've taken the intake almost completely off seems like there is something not letting it all the way up. Ill read more about that in the tech area.