My 92 F150 302 EFI is acting up again.

I noticed a while back when restarting my truck (when warm) I had to press the pedal all the way to the floor - like it was flooded - to get it to start. It starts fine when it's cold.
The last few days it gotten worse - I guess it's time to fix it!
Recently, about 5 minutes after starting in the morning it will stall (of course in the middle of a busy intersection!). I try to restart - pedal to the floor - it starts, I drop it in gear and it stalls again, and again and then again. I get over to the side of the road and gun the engine for a couple of minutes - plumes of black smoke rolling out. After 2 to 3 minutes of that the idle starts to stabilize and no more stalling. I'm thinking that there must be a sensor that's stuck or a little whacky.
Last night I pulled codes & the only code that came up was 179 which indicated that it's running rich and the HEGO can no longer adapt. So I changed the HEGO thinking that may be fouled. Same problem again this morning.
I also checked fuel pressure and had about 40 pounds with the key on, engine not running, 35 pounds with the engine running. As soon as I shut off the engine fuel pressure dropped to 0. Shouldn't it hold pressure for a while? Would this indicate a stuck injector or ??
Also checked for fuel in the vacuum line to the fuel pressure regulator. None evident.
I have also noticed that when I'm running on the front fuel tank it seems to drain quickly and will fill the rear tank. So I always use the rear tank first. I could not find any info on the fuel tank switch solenoid in my Chilton's.
I'm not sure where to go from here and need some suggestions.
Please help!
Thanks!!

 

when you push it to the floor the limp mode takes over.

iac, idle air control may be dirty or bad.

 

Diskguy, let me know if you figure it out. My 90 Bronco with 5.0FI and AOD transmission was doing the exact same thing. If I kept one foot on the gas and the other on the brake to keep the rpm's up when I stopped it was OK. If it stalled and you tried to drop it into gear at higher than idle it would stall again. You have to let it idle all the way down and then drop it into gear and it won't stall. Mine did the same thing with the black smoke and acting like it was flooded. I've changed a LOT of parts and haven't cured it yet.

 

you both need to read and post your codes.

 

Last night I pulled codes & the only code that came up was 179 which indicated that it's running rich and the HEGO can no longer adapt. So I changed the HEGO thinking that may be fouled. Same problem again this morning.
From what I've seen on this forum I'll be looking at my IAC, IAT and maybe the coolant sensor. Does that sound like the right direction??
Thanks for the help.

 

try disconnecting the battery so the computer resets itself.

 

No codes are present. I have five Ford trucks (87F250, 90F150, 90, 91, 93 Bronco's) so I know how to read the codes and reset the computer. But, in this case not only are no codes present but the last time I even had the check engine light come on on the 90 Bronco was for the TPS sensor and that turned out to be a short in the wire at the plug. Diskguy, when it stalls do you have to crank it for awhile before it starts?

 

Yes, gov2mod. It doesn't seem like it will start - then it revs and starts to chug.
I'll clear the codes & recheck this pm.
Is the Intake Air Temp controller on the intake manifold? I don't think I've ever checked that before.

 

I would have actually leaned more towards the FPR, but since its keepin right pressure, that cant be it. Holding it to the floor on startup actually shuts off the injectors. I'm thinking you may have some injector problems. Reason I say this is because you lose fuel pressure instantly...

Since these trucks were Batch fired, meaning all the injectors on one side are fired at once, a couple stuck injectors on one side could flood that baby out. Then when you hold it to the floor (shutting off the injectors) and start it, it will run off the little bit of fuel in the cylinder and then take off normally.

I know that last paragraph was a little difficult, but I'm thinking maybe you have stuck injectors. Stuck injectors could be an intermittin problem as you stated that it is.

 

Sounds to me like its that re-called check valve on the fuel system. It's filling the wrong tank and not holding pressure.

 

Do you know where I can find details for changing/fixing that?
thanks.

 

Ahhh ha. Memorex I think you got it buddy. Didn't even think about that one...

 

Well since my Bronco did the same thing and it doesn't have a second tank I don't think that's the problem. Concerning the fuel system I replaced the fuel pressure regulator, replaced the lower and upper manifold gaskets, took all of the fuel injectors to Napa and had them tested, cleaned, new screens and O rings and it still does the same thing.

 

I had a similiar problem with my 94 f250. Turns out it was a bad ECT sensor causing the computer to think every startup was a cold start. $20 from advance auto parts and all was fixed. (but you do need a big 1"? deep well socket to get the thing off)

 

Last night while warming up my engine I was checking things out and noticed that after about 5 minutes the radiator was still stone cold. I squeezed the upper radiator hose a couple times (also cold) and immediately coolant started to flow and things warmed up.
I then checked the coolamt level - a little low - & added coolant. I noticed the rubber on the radiator cap was shot. I replaced the radiator cap, disconnected the battery cables (to reset the computer) and cleaned posts & clamps. On a test drive last night everything ran pretty smooth. This morning I made it to work without a stall. I plan to change the thermostat first chance I get. Is it better to put in a hotter thermostat?
I know there's still some problems (fuel check valves?) but does it make sense that if there was an air lock at the ECT that would have caused this problem.
I'm still not convinced.
I'll post followups.
Thanks for the ideas! This forum is great!!