Car has been running fine. On the way home yesterday (25 miles) I noticed at the Stop Signs the idle was a bit higher then normal ( no tach). I get home, pop the hood looking for maybe a crack in a vacuum line... The lines look OK. I tap on the newly cleaned Idle Control valve, nothing. I pull the one (fairly new) vacuum line off the front of the Fuel Pressure Reg and the idle goes up a bit more BUT when I plug the hose with my finger is drops down to where it should idle.
I thought that was odd. The FPR is fairly new, the hose is dry /no gas smell, what the heck would cause air to get sucked into this hose since the hose fits tight on the regulator? I have another engagement so the car has to wait. I go to turn off the car and since I was jerking with vacuum line I have the CHECK ENGINE light on. Grab the 25 amp fuse and pull it for a moment and put it back in and go in the house. Go to leave an hour later and the car is happy. This morning, car is happy. So what gives?? The ECU needed to be reset?? not sure but the idle is where it should be

--
'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me http://home.no.net/ebrox/Tony's%20cars.htm

Bet you are right, it sounds like the ECU needs to be reset.

Quick story - After replacing my intake manifold gasket, my car would run well for days then all of a sudden it would start to idle crappy (ran like it did with the bad itake manifold gasket) and then throw a Code (113?) or whatever the code is for a fuel injection issue. I was ready to pull my hair out!! Tried the 25 amp fuse trick and the problem would always return. Reset the ECU and the problem disappeared for good.:)

While researching the problem in the archives another poster (Farm Boy) had made the point that these cars are fairly smart and their computers can learn "bad habits" which can be hard to get rid of. Maybe this is the case here? Was for me...
--
93 850GLT, 90 244DL 290k :)

I heard here (AB near Baltimore) that pulling fuse 6 from the holder in the passenger compartment will reset the system. It does when I do it.
The question is why it needed to be reset, i.e. why 'bad habits' would have to be unlearned - did you replace the FPR hose pretty recently? If yes that could be it. I hope you won't have to worry about it any more.
B