the problem is this.......
on first start of the day , no matter if it is cold or hot (weather ,that is) the engine idle bounces around . it goes from 300 to 700 rpm and almost dies. after a few minutes it normals out to 550-600 rpm. any ideas?

 

Any info? Like year, fuel system, mods, repairs, damage, mileage, etc.?

 

sorry. it's a 1988 4.9L with throttle body injection and 144,000 miles.
no mods yet. no damage . the last thing i replaced was the alternator and batt. i have recently noticed that i may have a bad head gasket. also do you happen to know how much horse power the stock 6 engine put out. if you need more info just ask.

 

If it has no mods, then it's not a TBI - Ford never put that on a truck, and only used it on a FEW cars.

For any EFI problems, your first step should always be to pull the codes, and that link tells how to do it with only a paperclip (or any jumper wire). There's also a link on that page to my full code list, which shows the connectors and how to install the jumper.

The most likely cause for any poor idle condition is the Idle Air Control solenoid valve (IAC), which you can find at this site. Sometimes it's the Throttle Position Sensor (TPS) or just a vacuum leak somewhere.

Another good read is the emissions sticker in your engine compartment (the one with the vacuum map) - it gives the tune-up procedure, which you should also do once you've fixed the idle, or if you can't fix it any other way.

I'm sure someone will post the exact number, but it's ~135hp@~2700RPM. If you want to bump it up without blowing a lot of money (on mods or gas), read Project MPG.