Question about 1990 Cadillac Deville

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1990 cadillac deville v8 runs rough after tuned when you give it gas runs rougher what could it be?

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  • Wayne Dillon Jul 29, 2010

    where is theEGRvalve MAP andISC located

  • Wayne Dillon Jul 29, 2010

    Where is the EGR MAP ISC located

  • Wayne Dillon Jul 31, 2010

    It has a trottle body will seafoam work on it as well?

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  • 4,472 Answers

It could be a lot of things. I would run some amsoil engine foam through the intake when changing the oil. Also some injector cleaner. I would check and clean/replace the EGR valve. then from there check MAP sensor, the ISC, as well as the connectors for both. Make sure alternator and the grounds and electrical connections are all good as well.
Thank you,
Lee

Posted on Jul 27, 2010

  • Lee A.
    Lee A. Jul 29, 2010

    If your planning on doing all of this yourself I highly recommend you pick up the service manual. This gives you illustrated instructions on everything. You can get them quite cheap on ebay and explains how to diagnose and repair every not and bolt on your vehicle. It is what the dealer mechanics use and I get them for all my personal vehicles to assist with repairs.
    http://cgi.ebay.com/ebaymotors/1990-90-C...
    Thank you,
    Lee


  • Lee A.
    Lee A. Jul 31, 2010

    Most likely yes seafoam will work as well but amsoil is the best.
    Thank you,
    Lee


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1 Answer

Have a 1990 cadillac deville engine runs smooth in park/,neutral when iput in gear and accelerate it shutters changed plugs / wires no help could it be tranny or cv joint no noises from either


Does idle rough in gear if so may have bad fuel injectors. not saying that it is not transmission or joints, need to make sure the engine is running properly first.

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Do 1990 cadillac deville cars have a V6 engine?


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Had a computer on my 1990 Cadillac Deville bad, after changing plugs, wires, cap, fuel injectors, egr valve, etc.

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