Hi all,

I have brought (mostly) back to life a 1988 2wd Ranger 2.9 manual transmission that I bought from a field in Texas. Advice on here has helped me to learn a ton. I'm a backyard mechanic trying to get better! I've read up on the next issue, but have not found the fix yet.

The ranger has been running great for me, but I have come across an issue that I cannot seem to figure out. Lately when I drive it, it has an intermittent hesitation, big power loss, and a lot of black smoke. It goes away after ten to twenty seconds, but will usually return. Does it two or three times in my 15 minute drive to work. Temperature, load on engine don't seem to matter. If I pull over, the idle dips to about 500 then surges to 1000. it repeats the dip/surge cycle 5 or so times then stabilizes to normal idle.

I have been trying to bring this truck to a reliableish daily driver, so I've replaced quite a bit. Things I have fixed/replaced:

IAC
MAP sensor
TPS
Computer ground (removed quick link and soldered)
Fuel filter
In-tank fuel pump
Injectors
Vacuum lines
Air filter
Plugs
Rotor/cap
Spark plug wires
Put clear line as vac line on FPR and observed no fuel flowing through
Timing


Replaced the ECU today with no change, so I'm reaching out for help. I've googled on the issue until my fingers bleed. Can't seem to fix it. Any advice is appreciated.

Thanks!

Scott