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1992 Eldorado
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1 Posts
Discussion Starter #1
Rpm jump to high when cold starting (2200 rmp). When take off battery cable and wait 15 sec. it's normal for two starts. Maybe related to braking, after braking few times rpm drop normal but then waving during brake, drop to normal when car fully stoped. Rpm stay's in normal drive in 1600 rpm.
 

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69 Thunderbird | 90 Seville | 03 Corolla | 89 Marquis(scrapped) | 72 Torino(scrapped)
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2,026 Posts
This can happen when the ISC is disconnected, has a bad(intermittent) connection, or is out of spec. Have a look at the ISC connector. 4.9L or Northstar?
 

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1992 Seville
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323 Posts
Just a thought - Check to see if you got carbon deposits on the throttle valves in your throttle body.
 

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1992 Seville
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8 Posts
I've been having similar problems with my 92 Seville 4.9, among others, that problem was solved with a new IAC and TPS. The plunger on the IAC was not retracting so that left the throttle open at startup, the TPS, I'm pretty sure controls the IAC motor, along with the coolant sensor, MAP, MAT. Sounds also that when your cruise'n it will find an rpm and kinda hangup there. Mine liked to find about 1600 rpm and would just take off on it's own. Becomes a challenge to stop a 2 ton vehicle that way. I'd appreciate hearing how you fair...
 
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