This thing is beating me down...

[DaBombDiggidy]

here's a story of how much i love my 1994 3.0 ranger lately.

I went on a 2 hour drive to pick up the title for my new project car (1993 FD rx7). On the way back, cruising around 70, the temp gauge starts to hold around the L. (only time iv'e seen it high driving). After this i am getting constant bouncing idle, sometimes settling around 500 sometimes around normal 800. The coolant gauge now will more often then not rise when i get to a light (up to the R or L) then drop seconds after starting to drive to normal temp.

Previous summer i had done the head gaskets, water pump, belt, and all other gaskets i pulled off. Everything to spec and torqued as per ford. I decide after this new problem to address the pesky timing cover gasket everyone knows about with these things. So I replaced that, the radiator, thermostat, fan clutch, gaskets, and overflow goes well. I flush the system multiple times and now the coolant is green and holding a steady level. The truck still does rise in temp when the idle is low though (tested holding the throttle around 900 and the coolant gauge wouldn't rise)

My idle is still low and
I checked my intake tube, there were very small openings in it so I replaced it and the idle is still low and
I checked the IACV and cleaned it, it looked fine and the inside looked like it's never seen an ounce of dirt. The idle is still low and
I pulled the sensor off the mass and the idle was perfect!!!
I got a mass off ebay and replaced it. The idle is still low and

Typically i have to wait for the truck to warm up (5 minutes) because if i touch the gas as its bouncing down i risk stalling it out. If that happens the bouncing idle is much faster and almost stalls on every decline. Today i went outside and turned the truck on. The volt gauge looked like this guy so i turned the truck off, it didn't turn back on. Popped the hood and fiddled with the wires a bit. Started right up and now my radio doesn't work.

as you can tell i am very close to just driving it into a ditch. please lend a hand.

some helpful info. I have had no check engine light pop up the entire time. The fateful day i started to have all of these problems i did not work on the truck nor did i for at least a week or two. The alternator ground wire is shady as all hell. The bolt stripped and i had to pinch it between the bolt head and gromet, it's shady but hasn't moved or given me an issue in 2 years (until now maybe?). The truck came with $*!^ HIDs, they sometimes flicker when i hit a bump.

 

[RonD]

Make sure there is a good tight ground strap from engine to firewall, usually from the drivers side head.

A loose one of those caused my gauges to do odd things.

Do you know it is overheating or is it just the gauge?
I know hard to tell.

Assume new rad cap.
My '94 with 4.0l used the heater core as the bypass, when core was partially clogged I would get random heat rises, PITA to find that one.
Anyway check core for HOT heat not just warm, or if there is an external bypass valve check it.

Does temp go up when climbing hills?
Or only at idle, if only at idle the water pump blades could be wearing out so at higher rpms flow is ok but at lower rpms flow slows too much.
Oops, new water pump

When you unplug the IAC valve does idle drop and stay steady at 500rpm?
i.e. is the computer causing the up and down idle via the IAC.

Unplugging the MAF puts the computer in Open Loop so it is running pre-set fuel/air mix based on Throttle position and ignoring most other sensors.
So computer could be getting incorrect RPM data from CKP(crank position) sensor or Cam position sensor