Page 1 of 2 12 LastLast
Results 1 to 10 of 13

Thread: 1998 chevy 1500 idle problem

  1. #1
    Junior Member
    Join Date
    Jan 2009
    Posts
    4

    1998 chevy 1500 idle problem

    hello, i just bought a 1998 chevy 1500 4x4 with a 350. after i bought it the drivers side head gasket blew. got that repaired and went to start the truck and it idled rough and was hard to keep running and would stall out if you hit the gas but if you feather the gas you could get it to rev up then it would smooth out at around 1500 rpm but as soon as you let off the gas it would drop down to around 400 rpm and almost die then hover around 5-600 rpm. it also threw a code for multiple engine cylinder misfire. here is a list of items that have been replaced:
    entire upper rebuild gasket kit
    valve seals with garage done valve job to grind seats
    new head bolts
    egr valve, was bad when i bought truck first thing to get replaced
    cap, rotor, and plug wires
    new plugs
    new distributor
    water pump
    serpintine belt
    cam position sensor, came with new distributor
    idle air control valve


    checked for vacum leaks and found one in the line for the brake booster got that repaired, now truck still idles really rough but if you hit the gas it will rev up relativley smooth but drops as soon as you let off gas. replaced iac valve still same problem. checked tps it is good. Have not been able to get on road to see how it drives. was just wondering if anyone else has run into this trouble. is it possible the computer will correct this if i drive it for a while or could there be something i am missing? Would really appreciate any help or advice anyone might have THANKS

  2. #2
    Platinum Member
    bradrhale's Avatar
    Join Date
    Apr 2006
    Location
    Texas
    Posts
    11,158
    disconnect the battery for 5 mins so that the ECM can relearn and reset itself. if you still have the same issues, continue looking for vac leaks. you have already replaced quite a bit of parts in your quest for solving the riddle.
    did you change the plugs before or after it threw the misfire code??

  3. #3
    Full Member
    Join Date
    Dec 2008
    Location
    Timmins, Ontario
    Posts
    29

    Thumbs up Must be something simple?????

    Try checking the spark plug order. You said multiple misfire??

  4. #4
    Senior Member silverhairdeere's Avatar
    Join Date
    Feb 2008
    Location
    land between the lakes tn
    Posts
    1,831
    take a multi-meter and check your iac valve and wireing as it seem as like it is holding it open like it should ans as it idles down it is causeing a misfire code . also ckeck the tbi gasket by shooting a little 10-40 atound base and see if it smoothes out .

    shd
    Last edited by silverhairdeere; 01-26-2009 at 02:28 PM.

  5. #5
    Senior Member
    leolkfrm's Avatar
    Join Date
    Mar 2008
    Location
    N.Y.
    Posts
    8,978
    Welcome to the forum
    did you use a scan tool to reset the distributer?, you may have a crossfire issue
    I believe on that engine the dizzy turns, does not affect timing, but can still mess you up with rotor location
    4 wheels move the body
    2 wheels move the soul
    B.W.A.I
    Snow is a lot like religion and a lot like sex....you never know when you are going to get it!....or how much you will get

  6. #6
    Junior Member
    Join Date
    Jan 2009
    Posts
    4
    disc battery started and idled fine until i put it in gear then same problem.
    replaced plugs as i put motor back together
    checked and rechecked plug wires multiple times they r correct
    no i did not use scan tool to reset distributor is that something a dealer is going to have to do?
    also did recheck iac valve everything ok there
    had no wd-40 or starting fluid to check around tb gasket will try that tommorrow and will call the local dealer to see what they say about reseting dist
    thanks for all your suggestions

  7. #7
    Senior Member
    leolkfrm's Avatar
    Join Date
    Mar 2008
    Location
    N.Y.
    Posts
    8,978
    it would be cheaper if a local mechanic could do it for you.
    4 wheels move the body
    2 wheels move the soul
    B.W.A.I
    Snow is a lot like religion and a lot like sex....you never know when you are going to get it!....or how much you will get

  8. #8
    Full Member red_onez71's Avatar
    Join Date
    Jan 2009
    Location
    IOWA
    Posts
    15
    a new fuel pump and filter fixed mine

  9. #9
    Junior Member
    Join Date
    Jan 2009
    Posts
    4
    called several garages around town here and no one wanted to help me said they dont have the equipment nesesarry to do that kind of work. called the closest chevy dealr in town and they said it would be between 96 and 144 dollars so i think i will just take it there

  10. #10
    Senior Member
    Join Date
    Dec 2007
    Posts
    2,206
    yeah you may need to have the cam retard adjusted after distributor replacement, i know on my 454 it has to be set at zero +/- 2 degrees (set with a proper scan tool)

    also has your fuel pressure and volume been checked? should be 55-60 psi and flow about 1 pint in 30 seconds i beleive.
    Gone.

Page 1 of 2 12 LastLast

Similar Threads

  1. 1998 Ram 1500 speedometer/brakes - help!
    By OldGrizzley in forum Dodge Truck Forum
    Replies: 7
    Last Post: 08-25-2008, 09:42 AM
  2. 1998 1500 5.0 no spark?
    By 69Firebird in forum Chevy Truck Forum
    Replies: 0
    Last Post: 06-23-2008, 08:17 PM
  3. 1998 chevy 1500 weird startup problem...fuel?
    By stevenskins in forum Chevy Truck Forum
    Replies: 4
    Last Post: 05-22-2008, 01:49 PM
  4. 1998 gmc 1500 4 x4
    By gravyk in forum Chevy Truck Forum
    Replies: 9
    Last Post: 01-08-2008, 07:04 PM
  5. 1990 chevy 1500 problem e brake light
    By josh030181 in forum Chevy Truck Forum
    Replies: 2
    Last Post: 08-27-2006, 11:29 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •