Our 1983 F150 has just started acting badly. Up until a couple days ago it purred like a kitten but is now missing terribly at idle and then stalling when shifted into gear. This is a essentially my sons vehicle (its been in the family for 25 years but he is just turning 16 and this will be his) and he has been taking care of it. The engine is the 6 cylinder with a carburator. He changed the spark plugs several months ago and it had been doing fine. After the engine started missing he looked at all the plugs and reseated them. They look fine, although somewhat sooty. Nothing changed with the missing. He adjusted the carburator and said it is wide open. We did change the fuel filter too thinking maybe it just wasn't getting fuel. Where should we be looking next since ruling out what I consider the basics? Any recommendations are appreciated!
Thanks,
Drew

 

How old is the Ignition system. Wires, distributor C&R, coil. Coils become weak w/ age. You mentioned they aren't burning clean. It could also be caused by poor fuel atomization from the jets. "Lucas" fuel cleaner.

 

After trying a few things (Lucas cleaner, wires/plus, etc) to get the truck running smoothly I gave up and took it to the shop. They've had it for a couple weeks now and have tested the compression (all cylinders are good) and have rebuilt the carburator (claimed it was flooding with gas). They say it still idles very rough. Anyone have any additional ideas, before it costs a fortune and doesn't get fixed. Can anything on the exhaust side cause this? It sounded stangely raspy when it was running. Thanks, Drew

 

Yes, a clogged cat or other exhaust restriction (collapsed pipe, muffler baffle, etc.) could cause this.

 

Well the truck has been in the shop for a month and a half and they are stumped too. They rebuilt the Carborator and thought that would do the trick, but it didn't. Supposedly tried all the typical thing that would cause this, but nothing is working. They disconnected the exhaust side, and still nothing. They did mention that it did not appear to be holding a vacuum like it should, but apparently have been unable to determine where there is a leak. Anyone have any suggestions on where it may be leaking which may typically be overlooked? Thanks.

 

I'm not that well versed in Carb'ed, but isn't there a Fuel pressure regulator. Anyway, the engine is either OBD1 MCU or EEC IV. I'll bet Error code scans will divulge something not visually apparent. You can do the tests manually: http://fordfuelinjection.com/?p=13 or do yourself a favor and pop for a $22.77 Code reader w/ digital numeric display & memory. Also comes w/ a great, informative, user friendly manual. You would think any reputable repair shop would have one laying around, as it works on all Ford vehicles from 81' to 95'. But it seems they seldom do. I guarantee they sell more parts & increase labor not using them! You can find them by calling around, or just order one on this link, ships same day. This is the only make (Equus/Innova) & model (#3145) I recommend, anywhere near the price. The only others I endorse are in the hundreds of dollars. http://www.handsontools.com/Equus-In...ol_p_5574.html Remember that the engine needs to be at norm. op. temp. when preforming the scans. It can even help locate Vac problems. Or it may tell you, your PIP sensor (aka: Stator/ Hall effect sensor) is failing. Which is what I would guess if the Vac sys was static! On the lines of a Vac leak thats hard to locate, a ruptured EGR diaphram will become problematic under load, but have no effect at idle (unless the EGR soleinoid is failing also). Those are some of the thing's that also tip their hands in Error code scans. Interpreting the codes correctly takes a little knowledge of the system overall. An EGR related code doesn't always mean replace the EGR valve. So post the codes on your thread if you decide to get one or your repair shop suddenly finds their Code reader.

 

Have you tried replacing or cleaning the inline fuel filter mounted on the fuel line intake at the front of the carbuerator?

 

Did you look at the dates of the posts?