1988 Ford Taurus. Idles rough, drives great going down the road. I have put a new throttle valve in it no change.Uses fuel like crazy 3.0 V6 Engine. Headlights Flicker as well as interior lights. At one point radio would turn off when I turned on headlights I played with fuse box radio works fine but have no dash lights now. Wiper delay stays on I have to pull the fuse to stop it. The previous owner has put all kinds of sensors in it so I really don't know where to start. Just bought the car las saturday and I'm ready to junk it this weekend. The engine seems to run great. I do have black crap coming out the exhaust. So if anyone knows anything about any of these wonderful and lovely problems please let me know before I put a sledge hammer to it

 

Clean battery cables and try a new catalytic converter. Sounds like it could be running rich or have bad rings in motor ( rings or converter).

 

I had a similar problem with the rough idle in park, but drove alright.. It ended up being my IAC valve. may want to buy a code reader and run the codes..

 

I agree. A code reader may help to pin down the basic problems as soon as you figure out the electrical problems - or the code reader could get destroyed by a surge or overload.

 

Unless the reader has overload protection.

 

Verify battery voltage and alternator output is correct. Then remove, clean and reconnect ALL grounds. Flakey grounds will cause all kinds of gremlins to appear. My 2004 Freestar LIMITED was starting by itself and power side doors worked when they wanted, turn the lights on and the radio would die, headlights would come on by themselves during the day and could not lock the drivers door because the darn thing thought the key was in the ignition. Ended up being a flakey body ground connection up under the dash board. Excessive fuel consumpion could be caused by a shorted O2 sensorwhich maynot set a code (Had this problem on my 88 Ranger 4x4, never set a code)