Hey all. I drive a 1996 302 5 spd. I've had it for a few years and keep it well maintained and every winter it does fine starting until now. It will crank over just fine and try to fire but will not stay on. just wants to bog down and die it seems. pressing gas pedal gets it going but if i don't keep the idle up for 10-20 seconds it will just try and die or fade out completely. I've had no problems before and only when its cold it will do this. it's been about 20 degrees on average so pretty cold for november. I'm kinda thinking its the coolant ignition temp sensor but i haven't gotten a chance to go check the resistance. any ideas?

 

might try to put some HEET in the gas tank and run it some... also how old is the fuel filter.... could be the idle air control valve.... on all my f150s with the 302 that was the first part i bought ...i beleive there around 50 bucks

 

As bobkyle2 said; Fuel filter or Idle Air Control Valve (IAC)

Does the engine finally run normally after it's warmed up to operating temperature
or are you not able to drive the truck at all?

I don't think it's the Coolant Temperature Sensor,
because when the engine is first started it's in Closed Loop Mode,
and the computer is not reading the coolant temperature Sensor until the engine is warmed up, someone correct me if I am wrong here.

What weight Oil is in your engine?
If a straight weight oil and since it's cold in Utah now, install a multi-weight oil.
I'm sure you have 10W30 or 10W40, I just wanted you to think about it though...

Respond back later as to what the actual problem was.

 

fuel filter is about a year and a half old but in 4 years that i've owned the truck i've put on maby 12,000 miles so not alot of use on it and i'm running 5W30 in my truck which i just recently changed. Yeah I'm able to drive my truck it's just cold starts thats hard..so now i guess i'll go look in my haynes at IAC test procedures. thanks alot and i'll let ya know what i find.

 

well i checked my IAC and got a reading of 10.1 ohms so thats right in the middle of where it should be. I emptied a tank and got some new gas so we'll see tonight if that works any better. any other thoughts or ideas?

 

Distributor Rotor may have a carbon buildup on it or it's worn,
you may try replacing it.

Ensure you have no vacuum leaks on the intake manifold or throttle body.

How old is your Air Filter?

Ensure your Battery is fully charged,
does it spin your engine over really fast or slow?

Last year, my 4.9L always started up okay, maybe spun a little slow though.
The engine did not want not idle smoothly even when warmed-up and
it would go dead at stop signs sometimes, it seemed to run rough!
I charged the battery and it idled and ran like a new truck,
so I replaced the battery and no more problems.

 

In response to 87 F150's comment on the ECT and closed loop. I was under the impression the ECT is one of those magical things that tell the computor to be in open or closed loop.

 

rotor is only a few months old along with cap and plugs and wires. fuel filter is not very old but i can try replacing it. the motor cranks over just fine it just won't idle when its cold without help for the first 30 seconds or so. once it's warm it shows no sign of any problem.

 

well put some new gas in one tank and made sure it was running that gas and let it sit overnight. started right up. put some HEET in the other tank and did the same thing and it started right up and has been since...so after wasting much time in the engine bay testing i've found my problem...bad gas. thanks all who helped and will keep in mind everything you've said in mind for the future. Thanks again

 

good thing man.... glad your back on the road!!!