I let my wife use my work van (her B2 died) and at first I suspected bad gas or ethanol.
It would surge and surge and then die eventually.
I popped the doghouse and found a couple cracked vac lines, fixed them and no change.
The last few days it got worse. Now it won't start unless I put my foot on the throttle a bit and then it still catches and revs a bit then dies and if you hold the throttle part open it keeps doing the run, die, run, die.... If I can get it in gear, then I can take off and get some power but it is still stumbling occasionally.
I swapped an IAC from a '95 5.8 in the weeds (looked close, plug matched) and it made no difference.
I put a MAP (?the stand alone thing w 3 wires and a vac line?) from my diesel (there were numbers that matched, plug matched) and then it wouldn't start at all no matter what I did w the throttle.
I put a used fuel pump in a couple years ago. ???
The check engine light has always gone on after a block or two as soon as ya gotta give it some gas, and then stays on forever as you drive.
Iread a post below about vac leaks in the evap lines and going out to look at that.
Sound familiar?
Any guesses?
'95 E-250 4.9 six auto ac-disconnected
THANKS!!!

 

Take it to Autozone and have them check the codes before you chase anymore ghosts. EFI is complicated but at least it will tell you why it's throwing up...

 

Your system should be OBD1 and most stores can't pull those codes. Go to fordfuelinjction.com for info on pulling the codes with a paper clip. Other sites have the info and code breakdown too. While the EFI is complicated it can be easily checked with a Haynes manual and a multimeter. Don't replace any component with out testing it first. On my past 3 4.9s the only issues have been the MAP sensor, loose connections, and leaking vac lines. Other trucks I have worked on have had faulty TPS, IAT, PIP, and IAC.
regards
rikard

 

Thanks for the info. I went to fordfuelinjection.com and printed the codes and instructions. I have a buddy that owns a small service station and I have worked on his rentals etc and thought I could get the code read there - way too busy. Thanks. When it's his stuff it's real important but if it's just the vehicle that I depend on for my whole business then - no big deal. He was going to change the iac before he even pulled the codes.
But... had a friend of a friend pull codes and bingo!
126 Map or baro out of range - went to the '89 bronco in the weeds and stole the map and it runs like a top. How simple. Hard to believe that such a common map - one thats in stuff from the 70's thru late 90's could cost 100 bucks at the parts store.
I forgot to mention that I am in the boonies and the local parts places don't scan and must think that no-one can get the internet here to order parts online.
Thanks for the help - I am going to keep that info handy.