3800 engine runs rough at cold start up

Tiny
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The pounds per inch changes on the scanner at higher RPM
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Sunday, May 6th, 2012 AT 1:22 PM
Tiny
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As you increase rpm, the voltage should respond imeediately.

Roy
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Sunday, May 6th, 2012 AT 1:38 PM
Tiny
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I took out the MAF and cleaned it the car started cold and ran better but not right Idle was all over and the voltage on the MAF sensor was at 2.60 and went up to 2.80 at 3000RPM
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Sunday, May 6th, 2012 AT 2:02 PM
Tiny
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I did find some small cracks in the top of the sensor looks like I must have hit it when I rebuilt the engine!
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Sunday, May 6th, 2012 AT 2:04 PM
Tiny
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Try tapping on t when it is running and see if the pitch of the motor changes

Roy
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Sunday, May 6th, 2012 AT 2:31 PM
Tiny
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I cant here it but I can see the RPM on the scanner change
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Sunday, May 6th, 2012 AT 2:36 PM
Tiny
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I think you need to replace the mass air flow sensor

Roy
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Sunday, May 6th, 2012 AT 2:41 PM
Tiny
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Ok Thanks I will let you know how it comes out in a week or two
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Sunday, May 6th, 2012 AT 2:56 PM
Tiny
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Good luck

Roy
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Sunday, May 6th, 2012 AT 3:13 PM
Tiny
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I haven't got the new sensor yet I got one off ebay and it was damaged so I'm waiting for a replacement. My dad looked at the car on the scanner and said the TPS was unstable and thinks it maybe a ground problem with the PCM do you know where the ground Is I cleaned the ones at the bell housing? I do see one looks like an 18-16 Ga. Wire by the battery tray that looks suspect but the bolt is so badly rusted I haven't had the time to get it off yet! Could this be the problem I forgot that the speedometer is off by 3 MPH could that be related to the ground? And can you tell me where the speed sensor is? Thanks

Ted
P.S. I'm still planing to replace the Mass Air Flow Sensor because its damaged
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Tuesday, June 5th, 2012 AT 2:35 AM
Tiny
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I replaced the TPS and its fine now. I also replaced the MAF sensor and that is unstable and bounces up and down. I had the Idle speed set at 600 R.P.M.'S and that sets a code for random misfires I turned it up to 750 and no comes but if I rev it up and let go of the throttle is drops to 450 and picks back up to 750 but sometimes it will stall. Do you have any Ideas?

Ted
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Thursday, June 14th, 2012 AT 2:22 AM

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