I'm having severe loss of power with my 86 F150 4X4, all the time, never a break. I have checked the fuel pressure; changed plugs, wires, cap, rotor, pick up, ignition control module, coil. Cleaned the EGR valve. Tested the MAP sensor, TPS. Replaced all vacuum lines rubber and emissions. I appreciate all the help in advance.

 

whats your fuel pressure? Have you changed both fuel filters?

 

Also Have you checked the Fuel pressure regulator is mounted to the fuel rail sitting on top of the injectors. It will have a vacuum line attached to it

.Also check the fuel filters. There are 2. One in front of the high pressure pump. and one further back and inside the tank selector / reservoir.
For the selector you 1st have to remove the skid plate. Unscrew the base of the bowl to access the filter:
This is what it looks like:
http://i608.photobucket.com/albums/t...ordfuelres.jpg

 

I have changed the filter in front of the high pressure pump on the frame rail, the other canister filter did not have a filter in it. The fuel pressure is 33 psi at idle and it does increase when you rev the engine.

 

Check timing.. i had trouble with my '86 where the bottem end of the rpm's it ran just fine, but once the rpms came up middle to higher (going by the sound of the moror.. no tac) it would just fall on its face. It wouldent even hold anything above 45 in OD.. turned out my timing was retarded almost 30 degreese.

 

Thanks for the info I will try and check the timing I have never done that before, and have no timing light. It maybe the weekend before I can do anything the truck died on me tonight and would not start back up so hopefully it can sleep on it and wake up in a better mood.

 

I agree, check the timing. I had a friend who just checked the timing on my 86 F150 that was experiencing similar problems. Before I took the truck to him I changed spark plugs, spark plug wires, distributor cap, rotor, breather element, pcv valve, etc. We also fixed a vacuum leak at the back of the carb. Still was not putting out the power that it should. My friend checked the timing today and said it was way off. Now after he set it correctly he said he can squeal the tires on the truck and there is plenty of power now.

 

Today I took the distributor out and brought the truck to TDC on #1 cylinder and put the distributor back in right and the truck would not crank at all. At this point I am completely out of ideas, so I put the distributor back where it was and it started, but once the truck gets to operating temperature it shuts off and will not crank for at least 8 hours. Still having the lack of power while it is running. Anymore help would GREATLY be appreciated.

 

I think the timing should be at 10 deg BTDC. Look for an emissions label under the hood.
When you say 'not crank' do you mean won't start? or do you mean the starter will not turn the engine over at all?
I would get a code reader and see if there are any codes.

 

By not crank I mean it wouldn't start, I even moved the the distributor back a forth trying everything with out any avail. Someone told me that it may be a fuel pump problem with the truck not starting while it is hot, what do you think?