Hey, guys. I have an '03 F-150 I bought used. It has 75K miles now, I believe.

For the past month or so, maybe more, sometimes, when you start the car, it will start, then stall almost instantly. The gauges will peg for a bit, then it will go back to 0, stay at 0 for a bit, then go to normal. (my Dad who's own Ford trucks since I could remember says it's normal.) The engine normally stalls in between this period, if you rev the engine a bit until the gauges go back to normal, it won't stall. Ever.

Also, a new problem (well, one I just discovered), I was driving on the freeway, and I noticed my a/c wasn't blowing that well, I looked at my gauges and realized my engine temp was on H (but not in the red). I pulled over, let it sit for 10-15 minutes, started it, and it was back to normal. I drove again, and it happened again. But it seems it only happens when the A/C is on. The odd thing is, it doesn't happen in the city, only when you keep the RPM at like 2K. I haven't tested it in Neutral and kept it at 2K to see what the deal is. I drove down south today on the highway, I had to pull over twice, I took US1 (a main street here in Miami that has lights and a 45 mph speed limit) on the way back, and it didn't even go above normal temperatures. I was thinking that it's the thermostat. But, I'm not really sure. Could you guys give me any advice for these two problems? They're really bugging me.

 

First problem sounds to me like an electrical problem. Battery,alternator, or something of that nature. Check the battery first. It seems to me that when the gauges spike, the truck is resetting. It could be something else too, just going by experience that Ive had.
Second sounds like thermostat is sticking.