I have 2 problems actually one is this strange problem. when I start my car the idle goes up, then down when its starts to warm up, when its warm idle is about 750 rpm. If I put the car in drive, the idle starts to go up over 2000 rpm, and it starts to hiss, I have to keep my foot on the brake hard to keep it from driving off.


the other is an intermittent miss at idle.

91 RS 5.0 lo3
no cat

what I have done,
checked trouble codes, code 54, and another one(forgot, im at work now) about low coolant temperature.

I replaced the fuel pump relay.
I replaced the Coolant Temperature Sensor.
Full Tune-up (plugs, wires, distributor cap, rotor button, pcv, fuel filter, checked timing)

cleared ECM of codes, and started it back up... still same two problem and now no codes.

I also replaced the TPS and re-adjusted that but no changed.

P.S
I'm using WINALDL I use the 'dash board' to set my TPS via the "TPS" box in the WINALDL dash window but I can't ever seem to get it to .5 barely moving it like a milimeter and it will change from like .7 to -.3, or from .7 to 1.2
.7 is closest I can get it.


I was thinking MAP sensor but would that only act up when I put the car in drive? I'm not seeing teh connection why this only happends when I put the car in drive. As far as the miss I was thinking ignition module. but I hate to keep throughing money at it without knowing exactly what the problem is, is there a way to find out with data logging?

any help would be apreciated.

I haven't ruled out doing a compression check, I just did one a couple thousand miles ago and they were all still above 100 psi, since then I have only driven it to work in traffic. It never runs hot, I have it setup to pretty much run at about 160 all the time.

Hey, this is the same problem I have.

What helped with my hiss was actually screwing in the idle screw a bit in to open it more.
That took care of the hiss.

I replaced every sensor, and distributor and wires, and pluggs and it did not help. I have new coil and it did not help. I am running out of ideas.
One thing to replace was a fuel pump and I am doing that pretty soon, so i'll let you know what happens.

You let me know what happened to your car, and what did you do!

Thanks.

Hello, I haven't done anything else to it since the first info in my post. I was goind to replace the fuel pump, and check again, then do distributor next. but then the battery died, and I decided if I'm going to have to drop the rearend to replace the fuel pump, and/or replace the distributor I'm going to wait until I get a walbro fuel pump, and a different rear end and replace the springs and stuff while I'm in there. Also I want to put a high performance distributor instead of factory. So I decided to put it in the garage indefinatley as a long term project and do it the way I want when I get the money which hasn't been since.