1991 6cyl 137,000 miles
 

Just bought the truck and love it. It is a 4speed man with OD gear.
Everything works great, but the temp guage never gets any further than right at the low/norm line. It has been really cold out here-Portland, Ore,
and I get heat out of the heater. Just wondering if this is something I should worry about? Also, this thing has fuel injection, I've always had carbs, anything I need to know about it-maintenance or anything. It seems to studder a little, but that may be me getting used to the gearing, Just got it Sat.
Thanks in advance.

I can't speak firsthand about the temperature, I am in AZ where overheating is more of a problem than underheating. :) But from what I have read on the forums here most people's temp gauge tends to run between the "n" and the "o" in "NORMAL" so that sounds about right. As far as preventetive maintenance, nothing special should be needed. I'd do all the regular stuff you do when you get any 'new' vehicle-- change out all the fluids, check the brakes, check the wheel bearings, etc. With it being that cold up there you might also have the battery tested, but that's about it. The engine itself is one of the longest-lived out there and should have plenty of life left in it.

congratulations and welcome.

My last 2 F150's were both cold blooded also. Warmups in the winter are long suffering. I'd wager you don't have a problem, but it wouldn't hurt to replace the thermostat, because some guys have put 160 degree units in these trucks, either because of heat in the summer, or because they reprogrammed the chip,and it was recommended.

I've got a '91 F-250 (5.4 EFI) that also never gets past about 1/3 on the gauge even on 90*+ days.

I'm in Milwaukie BTW. :)

Thanks for the info. I'm new to the newer trucks, but have quite a few of the older fords with the 6. great engine! I'm still having problems passing the DEQ. I'm failing the Emissions/Hydrocarbon test and posting almost double what the passing number is. I've changed plugs, dist. cap and rotor. The rotor did show some pitting along the contact edge, thought that was it, but just got back from deq and posted same results. My check engine light isn't on, would it come on if something major was wrong? The truck runs great. Any ideas are greatly appreciated.
Cole Portland, Ore.

generally an emissions-related issue will likght up the MIL-- but I'd pull the codes anyway, just to be sure. It's easy enough to do.

Also, you didn't mention if you had checked and/or replaced the plug wires-- that's an obvious possibility.


Also I forget, but 91 has the mass aiflow sensor, right? (I'm sure someone else will chime in here to confirm)--- if so I'd check that, that comes to mind.

Oxygen sensors come to mind too, as does a catalytic converter issue.

First things first, though-- pull the codes, see if the computer tells you anything-- if not, then go hunting for the issue.

Can I just go to a Schucks or someplace and have them read the codes? I asked last time I was there and they said that it wouldn't say anything if the Check Engine light wasn't on. MAybe they didn't want to go outside in the cold....
Don't know about the mass airflow sensor, probably a good time to buy a Haynes book for it.

Yeah they just didn't want to go into the cold. The computer on OBD 1 trucks will only flash a CE light on "important" codes. If your bored you can even do it yourself.

http://fordfuelinjection.com/?p=13

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