Engine Lugging and Radio Static

[Inbred Redneck]

I'm hopin' some of you guys'll give me an idea (I know there're no hard and fast rules) as far as when I might be lugging the 2.9 in my stock '87 4X4. ID plate says it has 3.73 and came with P215/75R15 and it now has LT235R75/15. Truck has 144K and seems to run pretty well, other than an occasionally uneven idle (1100 to 1400RPM) but I know that I don't want it turning over so slow I can feel each hole firing.
I'd never try to run it uphill at 1200RPM in 5th, but in 1st and 2nd I'm not bothered by revs that low. Is there a rule of thumb that applies to these engines that I can use, or just figure that if response lags when I give it throttle then I need to drop down a gear?
Now for the radio. Aftermarket Kenwood AM/FM/CD that sounds uh...well...all right, I guess. Less noise with FM than AM, but that's to be expected. Occasional popping and hissing, but a real whine that gets higher pitched as RPM increase. Whine disappears when I turn on lights, turn indicators (at least while they're flashing on) or stepping on brake pedal. Turning on/off fan makes no difference. First guess is a ground problem but it'd be nice if this is a common thing and somebody here could tell me to just change the blinker fluid, rebuild the firttzensplatzer, replace the teflon muffler bearings and it'll all be perfect. I guess if you tell me that I need to go through and clean every ground from the battery to the tail lights, maybe I'll have to consider goin' that route.
BTW, anybody got a favorite brand of muffler bearings or will generic Pepreilleyzone do the trick?

 

[tmcalavy]

Wire it direct to the battery with it's own fuse...sounds like it's wired to the ignition hot side now.

 

[RonD]

The muffler bearings tend to last the life of the vehicle in the '80s and '90s Rangers, it's the 2000 and up Rangers that have the high muffler bearing failure rate.

Radio noise that changes with RPM is from the coil, you need to install a condenser/capacitor on the "+" coil terminal.
It should have one but may have been removed over the years.

Condenser is the older word, Capacitor is the current word, they are exactly the same electrical component, just FYI

Lower cost Spark plug wires can emit radio waves which are picked up by the antenna and other wiring.
Carbon core spark plug wires are one long resistor so suppress radio noise, less expensive steel core don't.

 

[Inbred Redneck]

Damn! I was hopin' the plug wires 'n' such would last at least as long as the muffler bearings and blinker fluid. Seems to me that in the old days, carbon core wires were considered more fragile and prone to breakage. With this-here torque monster 2.9, I'm afraid the psychic energy from the mighty motor would radiate out and the poor wire cores might shatter and vaporize.
I've always preferred Autolite/Motorcarft parts for my Fords (don't ask about my attempt at usin' Champion plugs) but if you guys think that there's an aftermarket type of tune up parts (cap, rotor, wires etc.) I might be willing to go that route to save some bucks. Since the truck doesn't seem destined to get many miles each year, it may just behoove me to get OEM and figure they'll last as long as the truck. Don't know suggested life of tune up parts and frequency. I used to just do that kind of stuff when it seemed like the vehicle needed attention.
I know the thermostat was original up 'til a few months ago, water pump is still virgin (I think) and the factory front wheel bearings and tie rod ends just got replaced, along with clutch and rebuild of slave cylinder.
Oh, yeah, just needed a new coolant sending unit for the temp gauge. Infra-red thermometer showed operating temperature of 194F but the dash unit told me I wasn't but barely in the lower range for normal (that's the engine, as I be hard pressed to make any claim of bein' normal, myself) and now it's showing the needle up on the "o" in the "normal" bracket on the dash gauge. Hardly moves, even with the A/C on. Not used to that, as when my old FE engines got that hot I started worryin'.
BTW, thanks for the quick responses.