Engine miss.......AGAIN - Page 2
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HT4100 4.1, 4.5, 4.9 Discussion, Engine miss.......AGAIN in Cadillac Engine Technical Discussion; Well, it seems that when I said there were 'no codes', I meant the S.E.S. light wasn't on. apparently there ...
  1. #16
    MachX's Avatar
    MachX is offline Cadillac Owners Fanatic
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    Re: Engine miss.......AGAIN

    Well, it seems that when I said there were 'no codes', I meant the S.E.S. light wasn't on. apparently there are codes that come up that don't cause the light to stay on. Just on a whim I checked the history and came up with E34, and E71. MAP Sensor, anyone? And the symptoms of a bad MAP sensor describe how my car is running to a T. Now, is there anybody who can tell me where it is?

  2. #17
    behind-bars is offline Cadillac Owners Connoisseur
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    Re: Engine miss.......AGAIN

    Quote Originally Posted by MachX View Post
    Well, it seems that when I said there were 'no codes', I meant the S.E.S. light wasn't on. apparently there are codes that come up that don't cause the light to stay on. Just on a whim I checked the history and came up with E34, and E71. MAP Sensor, anyone? And the symptoms of a bad MAP sensor describe how my car is running to a T. Now, is there anybody who can tell me where it is?
    IIrc the map sensor is the little black box at the top of the engine compartment, On my 93 it is mounted toward the passenger side just under the crossbar that connects the strut towers.

    Id guess its about 3.5 - 4 in long and about 1.5 inches wide.

  3. #18
    Tailfin's Avatar
    Tailfin is offline Cadillac Owners Enthusiast
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    Re: Engine miss.......AGAIN

    Blah, sorry I took so long. The ignition coil is that little cylinder-shaped doodad that's right on/in the distributor cap. The MAP sensor is like behindbars said... If you're looking under the hood, towards the back, I believe the vacuum hose that goes from the throttle body to it is easily accessible, but given the kPa readings you indicated before, I wouldn't bet this as being the problem. If you take the vacuum hose off the MAP sensor, you should notice some obvious problems with the engine running.

  4. #19
    MachX's Avatar
    MachX is offline Cadillac Owners Fanatic
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    Re: Engine miss.......AGAIN

    Beautiful. 80 bucks for a new MAP sensor that didn't do a damned thing. I don' t know what else to do with this car. How can it run like garbage without tossing out codes or smoking or smelling. It sounds like somebody put a fat cam in it. Just chugs.

  5. #20
    MachX's Avatar
    MachX is offline Cadillac Owners Fanatic
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    Re: Engine miss.......AGAIN

    Well here's a new twist, was on a trip, and had to stop at a highway gas station. They had only 87 octane available, so I filled up. The car is now running BETTER on the lower grade fuel. What gives? I'm starting to lean towards the EGR valve not working properly, but there is NO way I'm dumping cash on another expensive part unless there is a way to tell for sure that it's the problem. It still chugs at idle, and still lightly shudders under hard acceleration, but under light acceleration the shudder is almost imperceptible. I managed to pull a couple of plugs, and they are clean. I didn't pull them all because it was hot outside and so was the car. Any more ideas, folks?

  6. #21
    HUF's Avatar
    HUF
    HUF is offline Cadillac Owners Connoisseur
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    Re: Engine miss.......AGAIN

    EGR valve does not care what octane fuel you use.

  7. #22
    TonyPat is offline Cadillac Owners Member
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    Re: Engine miss.......AGAIN

    Hi MachX,

    Did your problem solve, I got exactly same issue, and try a lot but problem still exist.
    Thanks

  8. #23
    dennis93coupe's Avatar
    dennis93coupe is offline Cadillac Owners Connoisseur
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    Re: Engine miss.......AGAIN

    Is a 5 year old thread. You might want to start a new thread in the FWD forum.

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