So i have a problem with my ranger that I see looks to be quite common with the symptoms on these forums but I haven’t seemed to find any good answer. My 1999 2.5 ranger starts fine maybe a little rough on cold days but nothing strange, truck runs fine when you start it, chokes great and everything, I can drive completely fine until I give it any decent throttle and push the clutch or put it in neutral it will slowly drop rpm’s at a steady pace until she stalls, proceeds to start no problem. It gets a little better when it warms up but if I go anywhere over 3k rpm it will stall out again. Truck also runs quite rich which is accentuated by my exhaust leak, I call it my redneck burble tune. Anyway, the truck is almost useless up to 3k which makes things kinda dicey, anything below 2500 in any gear that’s not 1st or maybe 2nd and it just groans and doesn’t really accelerate.

So far I have ruled out plugs, IAC, MAF, TPS, throttle body, compression, o2 sensors, PCV and probably a few other things but no I have still not done a vacuum test but I will update if that has any result

 

What were the results from the vacuum test?

Did you run a compression test as well?

I had the same problem that you had, no acceleration or power in 1st or 2nd. when i finally pulled the head off i saw recessed valves and the head was cracked. currently installing a replacement.