1992 5.8 F250 Idle Problem - Really wierd!
Problem getting worse and worse.
Idle surges up and down, about 70% of the time when the engine is warm. Sometimes it goes away completely. Please read all of the below points.
The Battery Gauge is very low without starting the car. It DOES start, even in 10 degree temps, so I dont think the battery is shot. The alternator charges when I hit the gas very quickly and efficiently.
The idle gets better when I put MORE draw (heat, more lights, etc.) on the electrical system, curiously, but it idles VERY low. (But the sturging stops or gets 80% better most of the time).
Now when I START the truck, i often hear an awful noise through the CD player, mid-low pitched noise for 3-5 seconds.
Also, my headlights are HID's,.. but when the truck is off they don't get enough power at the headlight plugs to power up. If I turn the car off while they are on (and only drawing 30 watts), they cut out within 10 seconds.
I am beginning to think this is a ground issue.
Also, my belt is squeaking, but seems tight. Could the belt also contribute to this?
The Idle surging has been steady through the following repairs:
IAC Valve, MAP Sensor, Vacuum Leak Repair, Sea Foam through Gas tank, New Battery terminals,FULL tune-up (Plugs, Wires, Distributor cap and rotor, Gas Filter, etc.), Reset computer properly, checked for unplugged items.
Car idles WORSE as it warms up, typically it runs fine upon first fire-up (when idle is high of course, it's getting more gas) But recently it's been getting worse, quicker.
I was told one of my plugs may be arching (but this guy is an idiot, and i just replaced them?) Not sure how reliable this is.
Yesterday the bat gauge waved up and down a bit, and the lights on my CD player pulsed a bit as well. Any suggestions?
The car has TONS of pick up, engine is responsive, and not sluggish.. except at idle.
I want to rule out inexpensive fixes before I waste time with the TPS sensor (since this is NOT a common issue with the 351 windsor from what I've read)
Can anyone offer any help? Nobody has a code reader for this vehicle and I'm a broke college student now, I can't afford to pay 100 just to have a code read, that's ridiculous. Please help.