Runs bad almost stalls

1994 CHEVROLET S-10
185,000 MILES
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ZR195
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I have a 1994 S10 Blazer 4.3 and up until last night it ran good. I went to start it and is all it will do is turn over, so i checked the the norm things like is it gas getting to the TB is the fuel pump even priming etc... And after a few min of attempting to to start the car on and off i got it to fire for a few seconds, not really running but shaking lol. I gave it gas and rev it up hard i got it to idle ok so i took it for a drive and had no issues. So this morning i went to go to work and did the same thing as last night not starting but this time well driving i was doing good till i got to a stop and then when i started to take off just as i hit the gas it started to spit and sputter bad, almost stalling but it did not. As soon as i let off the gas it started to idle fine but every time i would hit the gas it would run very bad almost stalling again. I am kinda at a loss as what to check next. Any ideas would be great... Thank you!

Matt
Aug 31, 2011 at 2:27 PM
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JDL
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How long since a tune-up? Any applicable trouble codes? Do you have the spider fuel system? It is noted for problems. Use a gage and check fuel pressure. With TBI around 10 psi. with the spider system around 60 psi, key on engine off.
Aug 31, 2011 at 2:41 PM
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ZR195
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last tune up as way b4 i owned the car lol about 50k ago i would say. No codes it is a spider system less then a year old. ill have to check the fuel pressure tomorrow when i can get use of a gauge.
Aug 31, 2011 at 3:41 PM
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JDL
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Let us know what you find.
Aug 31, 2011 at 3:57 PM
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ZR195
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checked the fuel pressure its holding at 57 to 60 PSI key on and arond 54 to 55 running it drops to around 40 to 45 when atempting to start the motor then right back up to 60ish when i stop cranking. So we checked spark in a few of the wires and some were weak but not enough to not start acording to one of my mechanics at my work. So next step was poping the intake to peak at the spider and there was some gas laying around and the guys told me that was the spider going bad so we put a new spider in and put it all back togother and it still would not fire so i checked the plugs they were fouled so bad so i put some new ones in and it started up fine and seamed to run fine till i went to leave work tonight i went out and started it took a second but started i rev it up a just to check and i felt that miss and spit and sputter again just slightly so i went less then a mile up the street to get gas and ran fine. Got my gas started fine rev'ed again and spit and sputtered again harder so i just took off got maybe a 100 yards and got worse stalled out and backfired once hard sounded like a gun going off lol never heard a car backfire that bad. so i pulled over and atempted to restart and nothing tried a few times and nothing so my friend was still at work she grabed a truck and pushed me back to work kinda funny as people watched that sight lol.
Sep 3, 2011 at 4:55 AM
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JDL
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Check spark and valve timing. Check egr, check for vacuum leaks. Use a spark tester. You could use a known good spark plug, break the ground electrode off, the spark should easily jump the gap to side of plug. If it won't, the spark isn't good enough. Just my opinion.

Try to see if system is running rich or lean. What is the 02 sensor signal doing, if it will run?
Sep 3, 2011 at 2:39 PM
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