Alright Guys, I just joined, 26 Im From Arizona and Drive a 88 F-250 with a 460, and I have an Issue. Its all Original including the Sparkplug Wires. This SOB can Fly down the freeway pass anything but a gas staion. I taken it all over in the 18mo I personly owned it, to Ut, Wy, Co, Tx, CA, and Mexico. Never had this problem but the engine seams to run poor when the weather is is hot, and under the hood temp gets high. It's mainly during Phx. Traffic, Engine temp is fine will get higher if I idle too much with A/c on, I know its really hot under the hood if its 110F. It runs as if the lacking fuel, If I shut it off and let it cool it runs perfect again. The fuel lines that run next to the Exhuast manifold are wraped in a silver tape heat protector, I have changed the fuel filter this past July when it hit 114F. This past week I went Hunting up in Alpine and I had to Climb a steap Grade that last about 3-5 Miles. I used to be able to Fly up hill at 75-80 A/C on but now its 55-60 A/C Off. So anyways I was flying up hill and as soon as the engine temp went a little up (Normal) around M the engine looses power. So is there anything I can do? Besides wait in till winter when its 80F.....

Just some FYI, I run Brand fuel (87&up) in it Shell, Safeway, Cheveron ext.... I know if runs real crappy if I feed it ARCO AMPM fuel. The Cooling fan runs great it always wailing and Roaring most of the time with the A/C on. Only thing replaced on the truck since 88 is the 02 sensor, Radiator/H2Opump, Map sensor, plugs/cap/coil, one low pressure Fuel pump, starter/reley and a ignition switch. Oh and removed the Cat it got pluged this spring so I took a Crow bar at it to remove the honey comb. Always gets 10-12 no matter what up hill down hill towing or not hauling or not, engine running or not. I Got 8mpg when the Cat was Clogged.

 

When is the last time the cooling system was flushed? I see the radiator/water pump have been replaced but if it's been more than 2 years, then do it- crud build up inside the system can become a problem very fast- especially in states like AZ.

Some rise in engine temp at idle [particularly in summer] is normal, but if you're going from one end of the gauge to the other [needle is moving over half or more of the gauge] this further reinforces my advice to flush the cooling system- and you just as well put a new thermostat in it while you're at it because you're going to have to pull it out anyway.

It also sounds like your fuel pump is overheating. Again I see that's been replaced but you don't specify which tank you replaced it in and if there's any relation to the symptoms if you're on or off that tank. Get an FP tester and see what it reads.

Start there and let us know what you find.

 

Yeah hey thanks, The cooling systems has been flushed I do it twice a year. And the Pump well the only new one is the Rear low pressure pump, but the High pressure pump is the Orignial I too thought it may be getting hot but I touched it once when it died and it was cool to the touch because of the cool fuel going in. It is OLD so Im gona see if I can get a hold or make gage. (Dad has plenty of gages laying around)