Fast Idle on 93 YJ 2.5L

[fish2222]

I am scratching my head.  I have a 1993 YJ w/2.5/manual.  It idles around 1300 RPM at all times, cold or hot.  I have checked all the sensors, TPS, IAC, MAP, and they all test good.  I have pulled all vacuum lines loose at the intake, and plugged them to see if it would drop, and it didn't.  The only one that seems to make any difference is the one that goes to the side of the valve cover, and it only drops maybe 100 RPM at the most.  Any other ideas?  Thanks!  Oh, one other thing... If I cover the TB opening with my hand while it is running, it will not die like I figure it should.  Do I possibly have an intake gasket leak? 

[LibertyPatriot]

If you can't choke it out by covering the throttle body, it's getting air somewhere.

[fish2222]

Im gonna spray some starting fluid around the manifold base tonight and see if anything happens...  I think it's funny how my manual says you can take the intake off by itself and change the gasket, but I am pretty sure you have to take the intake and exhaust off to change it.

[fish2222]

Does anyone know where the ground is connected from the gauges and/or the ECM?  The reason I am asking is that my volt meter is about 2 volts lower then what I measure at the battery, and the temp guage is about 20 degrees higher then what is measured with the ECM sensor.  (195 and the ECM sensor, 215 at the gauge)  I am wondering if maybe my ECM or the guages are not grounded well, and could be part of the problem too.

[fish2222]

I got it fixed this weekend.  It was definitely the intake gasket.  It had the stock gaksets that were two pieces (one intake and one exhaust), but the new one I put on was a one piece for both.  One side had burned out from an exhaust leak it looked like to me.  Anyway, I cleaned it all up, put the new gasket on, and now it idles perfectly.  Thanks for the ideas guys.