Repowered my '88 SPFI wagon with '92 version of the same tiny horses. (I know, Big Whoop). I bought this car new, and now has 245,000 on it. I don't know if I was just used to it, but the "old" engine would Idle down right away when stopping, while the "new" (125,000) engine takes takes about 8 seconds to do it in stages. Which ever way is right, how do I fix it? I have checked vacuum lines, timing, TPS adjustment, linkage.

 

Thanks, Jon

 

P.S. It runs and drives great. Just the idle problem. Since I have had the car since new, maybe I just deteriorated along with it, and don't remember what it was like new.

which intake manifold did you use?

 

sounds like an IAC problem to me

 

it wants cleaned

 

I'll wager a search for this problem will yield pictures and a procedure

I used everything off the "old" engine. Original manifold, throttle body, MAF, etc. Just placed the "new" block under the old everything else. Which scenario is correct? Fast down or slow down?Jon

Your idle should come down almost immediately. If it doesn't, it can increase wear on transmission components (clutch in a manual, torque convertor in an auto)

try cleaning the IAC (Idle Air Control)

Maake sure the FI coolant sensor

(two wire sensor on goose neck)

is connected and working properly

This is what the ECU

uses to know when to lower the idle.