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1999 Chevrolet Express 1500 Question: my engine starts missing badly after it warms up.

 

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gphvac, 4.3L V6, Lockhart, TX, May 23, 2013, 20:29
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Items I've replaced : Crank position sensor
neutral safety switch
ignition module
fuel filter
fuel pump
ignition coil
no code is being displayed , some times the check engine light comes on then the motor will miss fire and the light goes out , it normally happens at about 60 mph
any advice would be great.

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    pushrod May 23, 2013, 21:40
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    Plug wire(s) breaking down. Distributor worn, check for shaft play side to side.

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    gphvac, May 24, 2013, 19:14
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    Looks like that was the problem , I didn't feel like there was excessive wear in the distributor shaft
    there is a definite improvement in the way the motor runs , there is no longer a miss in the
    motor after warming it up or running it at 60 mph like before
    I replaced the distributor and the spark plug wires.
    thank you very much.

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    pushrod, May 24, 2013, 20:43
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    You bet! Should be near 0 play in the shaft horzionally. Glad you got it fixed! One more suggestion, like greg ask, crank relearn really needs to be performed! Also timing should be set, both need to be done with a scanner hooked up, make sure oil is full as rpm will be raised with relearn! Removing the dog house when you get to the shop will save you a little money. This is if you can't do these resets yourself. Need a scanner!! Now IF it is running just like it should you may have got lucky and have it in correct time and relearn was done by the computer but if the light is on or flashing those things really need to be done for top performance. Well even if light is not on needs to be done, it will bring it back to life + better MPG!

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    gphvac, May 26, 2013, 16:18
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    Thanks again, I think I might have right because it runs better than it's ever ran, I have thought about getting a scanner to set the timing, I don't mind taking it to the shop but I never know who's going to work on it, and it usually takes days to get it back, can you recommend a scanner that can do the job and maybe one that won't
    break the bank?

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    pushrod, May 26, 2013, 18:11
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    If it is running good with the power it should have, no check eng. light then dont try anything else! Drive it awhile and see what it does. Now, if C.E.L. is on get zone or advance to scan it for you, post codes and we will help more! Dont have to be done with a scanner, it is just more accurate. Glad to help!
    Oh yea, a scanner that will do this is not for a diy. Too much money for the average man unless using it daily. If you do take it to a shop ask if they can do this before getting it done!! Good chance the shop around the corner can't. If you know what i mean.

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  • Answer #2

    Greg's Orange Auto (13671 Answers) , Orange, CA - (714) 361-9386
    globalhelper May 24, 2013, 07:25
     Master

    agree with pushrod. did you relearn new crank sensor. seek relearn procedure on wwwalldatadiy.com

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