I changed plugs, dist. cap and rotor, and fuel filter. I checked the vacuum line to the fuel pressure regulator--no fuel coming out of housing nipple. Engine won't idle at start (have to give throttle for a few minutes to keep it running)--idles when it warms up, but sometimes stalls at stops. It runs fine at highway speeds.
Any information/help would be greatly appreciated.

 

Sounds like it's choking out on ya. Any history on the truck? Miles, mods, part replacement or repair (other than what you stated above)?

Could just use a good cleaning out with a can of Seafoam in the gas tank and run some through the brake booster line to the intake.

 

Thanks for the idea---I will do that. I replaced all as stated above, and the fuel pumps were replaced about 2 years ago. This engine has around 250,000 miles on it.

 

I cleaned out lines---still same--runs badly, hold the throttle at 1500 rpms, and the rpms fluctuate up and down--let off on throttle fully, and dies, recranks, then runs at proper idle, and seems to level out ok. I think I'm gonna take the egr apart and clean it.

 

The egr isn't activated until you are cruising or at highway speed. I'm a bit tired, but I can't remember the specs.

I wasn't thinking earlier, but I was thinking this was a carbed engine. If it is EFI, there is a chance of "2" things being wrong. The ECT sender may be bad or the ACT sender is bad. Both or one of them could be causing your problem. If most of these parts are stock or haven't been replaced in the life of the motor, these could be quick fixes.

IS this Bronco equipped with an O2 sender? If so, then this too could be part of your problem. O2 senders should be replaced around every 5 to 6 years.

Forgot to mention the PCV valve could be sticking, and allowing to much air into the intake. If it's stock for the life of the engine, it may be a good time to replace it. You can clean it for a quick fix, but I would replace and only replace it with a Motorcraft one.

Another thought, if EFI, then the IAC valve may need to be cleaned. This is a common symptom on older motors with a malfunctioning IAC valve. You can use some carb cleaner and a Q-tip to gently clean it out. Remember to disconnect it before cleaning it and you should be careful not to allow cleaner into the solenoid part of the sensor.

 

No sir, no 02 sensors. I'm gonna check the pc valve. Thanks for all your guidance.

 

No O2 sensors, then this is a carbed '86, 302?

 

No sir--it's efi with the high rise intake. I checked where a pc valve would normally be located--just has hose running from oil fill cap to air filter housing with factory elbows--has a pc filter, but no valve with the usual inner trim (or plug). I cleaned the IAC--no difference. I disconnected the fuel pressure regulator, and it started running normally--but no fuel pressent at the line nipple.

 

cranked when cold again--started same stuff, then stalled out. Recranked, and all ran good, like something reset itself--ecm maybe?

 

I feel foolish--I looked under at the exhaust system yesterday--didn't see any 02 sensors--I'm used to one in front and behind the cats--looked again this morning--did see one sensor hidden behind where the exhaust manifold bolts at the flange to the rest of the exhaust--gonna work on replacing that and see what happens.
Thanks again.

 

Went to buy 02 sensor this morning--started stalling and quit--would crank back up after about 5 minutes--got it to a repair shop to see if they can do better--I'm thinking now it's the pick-up pump in the tank.

 

It does have a PCV valve.

 

Any idea where it's located?

 

If Im not mistaken, on both my '90 and '92 302s', the PCV valve is located rear of the passenger side valve cover. It should be there, unless its been modified to just exhaust blow-by down under the motor as I did on my old motor since the blow-by was so excessive. The hose running from the or near the oil filler cap is the fresh air line from the air filter box for the engine.

You mention that you think the fuel pump is having problem's...do you have a fuel pressure gauge to check it with? If not most part stores will let you rent and simply give you your money back when you bring the tool back.

 

well it's at the garage--hoping they can do more than I could.
Thanks for all the input and information.
I think the next vehicle I get is gonna be in the 60's group---I'm gettin tired of computers and all the related aggravations.