Please help me before I pull my hair out. My son bought a 96 blazer- took it to two different garages and the MAF sensor was replaced along with the TPS. Then the starter went out so it was replaced also. The vehicle runs fine when you first start it up ( When ithas set overnight), and you can run it for 10-15 miles with no issues but as soon as you shut it off and try to restart it the only way it will start is if you hold the pedal to the floor like you do when it's flooded. It will then spit and sputter and not run longer than 30 seconds without having to restart it again. It only registers about 130 degrees or soon the temperature gauge and the motor doesn't feel the least bit hot. It's almost like 2 different vehicles.
I have had alot of solutions threw at me and this is what has been done so far:
MAF-replaced
TPS-replaced
starter-replaced
battery-replaced
new fuel tank
new AC Delco fuel pump
new plugs and wires
new rotor
Cleaned EGR and IAC valves
fuel pressure is 59-60psi
If you could just start it up and not have to shut it down I don't know if it would ever give you a problem but stop by to get a tank of gas and you just might have to push it home. PLEASE HELP this is getting expensive

 

From your information, I would do two things:
1. Replace the thermostat. 130* is far too low for an opeerating temperature and can cause drivability problems.
2. Have the ignition control module (ICM) tested. The test needs to be run about 10 times in a row to get the unit good and warm, because if they fail it will be when they are hot.

 

THANK YOU rriddle3 for your reply!!
Just an update-replaced the thermostat and now it registers around 180-190 degrees, so this is much better.
I also had the ICM tested when I went to the parts store after the thermostat and it tested fine. The guy checked it at least a half a dozen times so I'm pretty sure that is not my problem so I guess I'm back to square one again, any more ideas? The parts guy told me he would probably try the fuel pressure regulator next, I was thinking more on the line of a stick of dynamite (Just Kidding)

 

FPR is a possibility. With a fuel pressure gauge on the test valve, turn the key to 'on' and the pressure should be ~52-62psi. Turn the key to 'off' and the pressure should not drop more than 2-3psi over ten minutes, but should never go below 51psi.

 

I know what the fuel pressuregauge reads (59-60 psi)when the key is on but I'm not sure when the key is off, I'll check it out tomorrow and post the results. I'm just a little frustrated at this point. I forgot to list it in my first post but the fuel filter was checked but not replaced
had a new aircleaner installed
and an oil change less than 100 miles ago.

Friday was spent installing the new gas tank and fuel pump (got the brand spankin new A C Delco fuel pump for $125 on ebay, shipping included still sealed in originalfactory box) GREAT buy!! (Even if it didn't help)

Saturday was new platinum plugs and wires, ALL six and it wasn't easy

Sunday was new thermostat installation, and tested ICM (Ignition Control Module) but that checked okay. The rest of the day I read hundreds of posts on this forum to see if anyone else has a blazer as crazy as this one. If you could see how SMOOOOOTH it runs when you first start it (no quiver in the engine, no tailpipe rattle or anything, just insert key in ignition and turn and it starts like a champ)and then see it as soon as you tryto restart it you'd swear it was possesed(TOTAL OPPOSITE, crank, accelerate, crank some more, acceleratethen throw in the towel knowing that tomorrow is another day.

 

Just be sure that you don't skip the 'on' position reading before you check the 'off' reading since it is a bleed down test to rule out the FPR. How did you check the fuel filter without removing it, since that would have been the ideal time to change it if it has more than 30,000 miles on it.

 

Did have the fuel filter off, it was the only thing that looks like it had been replaced on the vehicle. Blew air thru it and it seemed like it was very open. I totally get your point that if we already had it off why not replace just so you don't need to give it anymore thought. This WILL be done tomorrow, just don't have time to mess with it today. I have already purchased the NEW fuel filter and you have an excellent point and it is a very inexpensive item, I guess with as crazy as the thing acts I thought it would have to be something far more complicated than a fuel filter but I'll still eliminate that.

Now for the readings on the fuel pressure gauge
I hooked it back up today and when it is "on" it read 59-60psi
when it is "off" it read 52-54psi (5-10 minute later)
and I looked at it again about 1 hour after I turned it off and it readaround 30psi
I know you said it should never go below 51 psi so what does all this mean? Do you think it is the fuel pressure regulator at this point? THANK YOU rriddle3, you have no idea how much I appreciate you taking the time to help me.

 

I think we're getting somewhere. Read this write-up that Kyle posted about fuel pressure diagnosis, follow the applicable directions, and let us know.

 

Read all of the fuel pressure diagnosis write up. I do know that we have no visable leaks as it is currently sitting in my spot in the garage and everything is dry underneath. My son is going to install the fuel pressure regulator in it tomorrow. I have already purchased the part. I will post an update one way or the other tomorrrow. I truly hopes this does the trick because we live in Ohio and they are calling for possibly 8-10 inches of snow and my Pontiac Grand Prix wants to get back in the garage. THANKS rriddle3 for the reply!

 

Today the new fuel pressure regulator was installed. It will now get up to 68psi with it "ON"but not running. When you turn it to"OFF" itdrops off faster than it ever did, I'm talking it will be down to less than 40psi in 2 seconds and by the time 5 seconds has passed it will be at zero. We tore it down a second time to be sure there wasn't a leak and everything was dry. We checked the spider assembly (I hope I'm calling this the right thing) and there was nothing visually wrong with it that we could see. We did put new gaskets on the spider and plenumas well as new "O" rings.
Is there a possibility that even though the spider looks good that there is still something wrong with it? Any ides as what the problem could be? We tried to turn it over (momentarily)and it pretty much just spits and sputters .