Van troubles- need help!

Discussion in 'Shop Talk' started by Willowynd, Oct 27, 2006.

  1. Willowynd

    Willowynd Well-Known Member

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    My van (95 GMC Vandura 2500) has been having issues off and on (lately most of the time) for the last 3-4 weeks with running properly. Initially it would rev and wane, causing hard shifting (automatic tranny) and difficulty getting up to and maintaining speed. We changed spark plugs and wires, distributor cap, air filter, changed oil- did not work. Took in for diagnostic- they said TPS was bad. My son replaced it and it improved the reving but now it acts like it is not getting enough gas/ steady supply of gas (will buck when starting off and then occassionally when trying to get up to speed, will die when I slow down or stop or put in drive, I need to push the accelarator way down to get it to go faster ) The engine light will come on after a while of this. Some mornings (I do a paper route) it will die 5-7 before even making it out of my driveway and several times while delivering. We thought the TPS we installed might be faulty, so replaced it again- still had the problem. Changed the PVC valve and the fuel filter- still acting up. The odd thing is it is not constant. Like yesterday- in the morning during paper route- ran badly- died 5 times- did not want to go over 45. Then that afternoon I had errands- 4 hours I ran all over- interstate included-it ran great. Ran great this morning during paper route- then this afternoon took son to work then on the highway- it started in again. I drove to AutoZone where they said I needed to unplug the battery for 5 mins- as the computer was still thinking the old part was in, then reconnect it. Did that. As soon as I pulled out of the parking lot it acted up again. My mechanic cannot get me in until next week and I depend heavily on the van- its my only vehicle and I live in the country and my husband is living out of town for work. My teenage son can do most things with the van if I know what the problem is- any ideas? BTW the current engine (I blew the last one from forgetting to change oil) has about 90,000 mi on it- tranny replaced about 60,000 mi ago, the engine is a 350 5.7 liter.
     
  2. skruzich

    skruzich Well-Known Member

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    Take it back up to autozone and have them read the codes again. IT should tell you what is wrong. Sounds like O2 sensor is going out.
     

  3. wilderness1989

    wilderness1989 Well-Known Member

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    Have the fuel pump pressure checked, same symptoms as my '95 Chevy 1/2 ton and it was the fuel pump. Beware of Autozone type store code readers, if you want the codes checked pay a GM dealer to do it. Parts store code readers are used to sell parts that you may not need. I'm retired but I worked 30 years as a Chevrolet master mechanic. My 2 cents.
     
  4. ovendoctor

    ovendoctor north of the lift bridge

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    fuel pump or injectors
    the fuel pump is in the tank on that van

    the injectors are on top of the throttel body[2 of them]
    check the wiring connections to them
    I am cleaning my shop out pm me if you need parts[parted out a 90 and a 93 van]
     
  5. Cabin Fever

    Cabin Fever Life NRA Member since 1976 Supporter

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    The fuel pumps on 350-V8s are notorious for failng. The one on my 1999 pickup went out at around 100K miles. People who I talk to that have GM 350 enegines all have fuel pump problems at around this mileage (+/-). My pickup now has 185K miles and I have never had an injector problem. My bet is on the fuel pump. On the other hand, my understanding and experience regarding the fuel pumps is that they go all at once. In other words, you get gas or no gas, none of this poor performance stuff like you're experiencing.
     
  6. mistletoad

    mistletoad Well-Known Member Supporter

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    My car (which has nothing at all in common with your van) acted like that for a couple of years before someone suggested cleaning the throttle plate. It's a five minute job at most on my car and worked like a charm. I can tell when it needs doing because the symptoms return. Not saying this will solve your problem, but it might be worth a try.
     
  7. morrowsmowers

    morrowsmowers Well-Known Member

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    That's my thoughts exactly -- if it's not an EFI engine is probably has a throttle body assembly -- just a little dirt will gum up the works -- our old van had to have service on the throttle body every 2 years -- even was sensitive to the type of gas I used. Dealer would charge about $80 for service but they actually disassembled the unit, cleaned it, and reinstalled it with new seals. Local service guys run chemicals through to clean it for about $55 -- I'm told you can do it yourself for about $25.

    Ken in Glassboro, NJ :rolleyes:
     
  8. skruzich

    skruzich Well-Known Member

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    I don't know about that. the one up town has a snapon code reader the same one my uncle uses in his shop. As long as you get the codes, you can isolate the problem.
     
  9. agmantoo

    agmantoo agmantoo Supporter

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    Temporarily disconnect the egr valve. If the problem ceases the egr is defective.
     
  10. jerzeygurl

    jerzeygurl woolgathering

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    check for vacuum leaks and check the EGR valve
     
  11. skruzich

    skruzich Well-Known Member

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    I would agree with jerzygurl. check for vaccuum leaks. Chances are that whoever replaced the tps knocked a vaccuum line lose or broke one.
     
  12. zant

    zant Well-Known Member

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    Check vacuum leaks,fuel pump pressure and if catalytic converter is clogged....Vehicles have problems,reading material has issues.
     
  13. fixer1958

    fixer1958 None of the Above

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    The egr is not going to make it fall on it's face like that under a load. It will act like that at idle. I say it's the fuel pump or worst case a converter. Fuel pumps are a way to common problem with GM and the symptoms are as described.
     
  14. dodgewc

    dodgewc Well-Known Member

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    Sounds to me like you have a problem with fuel volume. Don't worry about the nonsense with the code-reader gang. (no offence intended) A fuel pump can produce the correct pressure, but ain't worth a hoot without volume. (just think of the volts/amps relationship)Be willing to bet a new pump and inline filter (located at the front of the tank) will fix you up! Brian ASE certified Master Technician (for what thats worth) plus about a hundred or two GM certifications.
     
  15. skruzich

    skruzich Well-Known Member

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    one other thing can do that beside fuel pump or converter is a blown head gasket in between the cylinders.
    Another thing that can do it is a jumped timing chain or belt.