Timing problem early 90s 5.0 in 85 Ranger

[Danger4x4Ranger]

Second seperate post for another question i have regarding my 85 ranger. Bought it for cheap and has plethera of 4x4 upgrades mostly procomp parts new wheels and items easily parted out worth more than i paid. Needs a tune up and new map sensor looking to do new distributor, wires and plugs, map in next week or two. Has a weird timing problem, unsure of miles on the engine, odo shows 51,999 im sure its clocked over once maybe twice. It has, what my buddy believes is, a 92-94 5.0 in it but runs strong. Said it was on a guess due to the plastic 5.0 EFI plate on top of the engine. Looked about right to me. Im guessing the engine prob has min of 200k on it for fair assumption. Every 2-4 weeks the engine gets rough, have adjusted the ign timing with the distro seems to help clean it up some but temporarily. Almost seems like the distro shifts by itself a few degrees high or low. Its been ok for 3 weeks now like it was when i got it a while back but im concerned its more than needing plugs wires etc. sometimes seems to run rich and then like it doesnt get any fuel. we also put a time light to it and dialed it in as close as we can but it still seems to act a little shifty. Will have issue where starts rough goes to idle fine then when its in gear it will die or shake the whole truck to stall. If stopped will die in a min or two unless im in neutral and keep feeding it gas. Could there be any major issues besides timing, fuel/air mix, filters or faulty map sensor causing this? Id like to know further possibilities before picking up these items and it still acting weird after i install. Never messed with a ford til now and really wanna fix this girl up and get her running perfect for the summer with no issues for a long while.

 

[85_Ranger4x4]

Loose timing chain? Ford was good about using the nylon chains so the would be quiet. For the record I can't say as I have ever heard my double roller. My original chain was worn enough I could almost work it off the sprockets, I never ran it with that chain. No idea how many miles are on the engine but it is not new by any means.

Might check and make sure the rollpin is ok on the distributor drive gear too (and the gear itself for that matter)

There is a date code above the starter cast into the block that will give you a rough idea what year it is. It is hard to tell on someone else's project by the stuff bolted on it. Mine has a 4bbl intake, Duraspark ignition and an Explorer belt drive accessory system. So is it a 60's 289? 1985 5.0? 00's 5.0? It is an '87 but has nothing '87 bolted on the shortblock (even has '89 heads )

 

[RonD]

Assuming TFI ignition?

Do you have a timing light?
And is the timing off when engine runs rough, pull the SPOUT and see if it is still at 10-12deg BTDC.

TFI module and computer don't actually know what the spark timing is.
They both assume base 10-12deg BTDC and go from there
The distributor does have spark advance springs inside, centrifugal advance for RPM curve, if there is a problem in there then timing could for sure change.

 

[Danger4x4Ranger]

Dont have timing light. Let my buddy who is a former ASE certed mechanic mess with it but he didnt have a light to get detailed. Made a few minor adjusts plus i changed out all the plugs and it cleaned up but it keeps going into stages where it seems like it gets no fuel. Hoping it just needs the mass air flow replaced on the intake and not a new sending unit. Idle stays rough but when i lay into the gas it goes no issues however if stopped have to feed it or will stall out. Most of problem is from a start up or sitting in traffic. once out of park and shifting to rev ntl or dr will die immediately. I swich to ntl or park start it and treat it as a standard trans give gas as i change to dr/rev and pull out it will go but hesitates until about 25mph but cleans up after about 5 mins driving until it decides it has no pwr and stalls out. Just becoming a nuisance as i cant diagnose the issue to one specific part of the drivetrain