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1994 deville
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51 Posts
Discussion Starter #1
1st when driving around I sometimes feel like the idle control is playing with throttle as I drive and letting off gas feels like its rite there so Im going 18 let off gas and it kind of stays there till brake is apllied then will slowdown... car to me idles nice just that feeling like that idle control is moving while driving is that normal in park revs right up and then right down I here theres a special way to change out the bad batt the car relearn idle? it looks like it was just replaced before I got it should I do that procedure or not worry
 

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1992 DeVille
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2,339 Posts
swat455 said:
1st when driving around I sometimes feel like the idle control is playing with throttle as I drive and letting off gas feels like its rite there so Im going 18 let off gas and it kind of stays there till brake is apllied then will slowdown... car to me idles nice just that feeling like that idle control is moving while driving is that normal in park revs right up and then right down I here theres a special way to change out the bad batt the car relearn idle? it looks like it was just replaced before I got it should I do that procedure or not worry
The car will learn idle as you drive it. But the proper procedure has been posted here. I'll post a pic of it incase you wanna do it. Sounds like its operating probably as it should

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Isc max extension procedure fyi

 

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1979 Coupe deVille, 1995 Sedan DeVille (sold)
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1,846 Posts
If you are feeling changes while pressing on the gas, that is not the ISC.
How fast is the engine running at idle?

Another thing which can affect the idle is a dirty throttle body. Remove the air cleaner and pull back on the throttle. Clean both sides of the throttle plate. Also check the EGR tubes beneath to ensure they are clean and clear.

What was your second question?
 

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1985 Sedan DeVille
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1,883 Posts
The computer is supposed to take over with the ISC when you take your foot off the pedal (throttle angle is zero) but its possible for the TPS to be misaligned or defective and cause it sooner. In my experience, stumble at tip-in is usually related to EGR, you can test by disconnecting the vacuum line at the solenoid and stick a screw in the hose, then drive around for a bit and see if it changed anything. I've also had surging from timing misadjusted, you can test that by seeing if it gets worse under load (turn AC on/off, turn steering wheel to trip the pump switch, etc). Also the cruise control cable can pull on the throttle blades if the cable is too tight--the diaphragm heats up when the engine warms up and causes small change, if the cable does not have any slack it will pull the throttle.

Could just need a tune-up
 

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1994 deville
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51 Posts
Discussion Starter #5
no probs when pressing on gas she wants too go.40,000 mile car and just did cap wires plugs and coil ran good before .more of an age issue in which im glad cause the orig cap was corroded.. no pinging etc . just when im driving and let off gas feel like its right there could be me trippin lol ..I need to get these books as I did with my roadmaster 3 books which im trying to get rid of to get the others.. as I see it looks like with the cad we can see readings for codes, temps for air mtr, tps, ox sensor, injector % and more from our data or ac contro the road master would show codes and mtr temp and i think air door stuff but no act real data that's why I prev ask about tunerpro was needed to see our car data . do you have the tps check and map check too ? and is there a link too get into my info and check too see if all is well .until I can get these books .. also I have no check eng issues but I here some codes will not trip light and just be stored im mem
 

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White Diamond '03 DHS (with DTS floor shift)
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86,781 Posts
You get to the data via the onboard diagnostics. There is a link in the DTC Sticky, but I'm not sure if it tells you how to enter the data mode and even if it did, you would not be able to decipher the codes without a FSM. I think you are stuck until you get a set.
 
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