I have a 1993 Ford E150 with a 351/4 speed automatic conversion van that I have posted many threads about here on the FTE forum.Here's another one............3 months ago I replaced the temp sensor,airchrge sensor and fuel pressure regulator because the van was running way too rich and flooding out. I had a code 51 for the check engine and these are the items that Ford suggested to replace. I did so and the van ran well for 2 weeks.then the fuel pump went out. I replaced it and the fuel filter and it ran great for approximately 6,000 miles. This week it started to act up the same way......only it's not flooding out - just no power and eventually runs only about 25 mph. I changed the fuel filter and regulator again to no avail. It is not showing any codes... and it is NOT starving for fuel....if you run it down the street when the motor is cold it runs fairly well........after about 1/2 mile - it hardly runs...bogs down and the trans cannot shift because of improper vacc.I should mention that this van just passed the emissions test and the exhaust is not clogged up.The gas filter is not clogged and the pressure seems fine. Any ideas???? I am a certified mechanic by the way.....Ford has no ideas other than to keep replacing parts until I get the problem fixed....try telling the customer that.....

 

Mine is doing something similar. 1995 E150 351 117,000 miles. When coming back from West Virginia this weekend, it started dropping in power and speed until I had to pull over. It wouldn't stop, but there wasn't ant throttle. Stopped the truck and started checking the basics, plugs, wires, cap and rotor OK. No codes, (yes I carry the code checker with me), as soon as the van had a chance to cool down I tried to start it and it started like nothing was wrong and off we went for about 15 miles and it happened again. Same thing on Monday and Tuesday going to work. I suspect someone has run into this before so I hope thay can help. Since it appears to be heat related I suspect a sensor problem, but it didn't throw a code, so I'm not sure where to start....if I figure it out, I will post the results....Good luck!

 

I saw the post by BroncII and decided to add the following info about my case:
My van has 126,000 miles on it. I checked the air flow meter, vacc lines, etc. So far all o.k. I did notice that my engine temp is coming up way faster than normal. With an outside temp of 40 degrees and the van sitting all night it only has to be driven about 2 miles and it is up to operating temp........but not overheating. It never does overheat, just heats up rapidly. Then I have NO power and it shifts terrible...almost like a major vacc leak somewhere. I thought the catalytic might be clogged, but the exhaust is open. ??????????????????????any thoughts??????????????By the way.....when I replaced the fuel pump in August, it was with a motorcraft updated replacement part......not an aftermarket part.

 

Iv'e seen similar posts for this problem in the electrical forum most were blamed on the TFI module located under the dizzy when it got hot the problem surfaced and if the truck sat awhile like 15 or 20 minutes everything would be fine.

Since having eliminated some of the other things like fuel related I would look into the TFI computer module.

One other thought Vapor LOCK Its not likley but anything is possible.

 

Thanks for the input........the problem is that since it started doing this again it has gotten continually worse. Today I ran it just a few miles and could not get it above 5 mph. I held the throttle a steady rate and the motor was surging just barely above idle and back again like it wasn't getting fuel. When I parked it it was barely running. I waited about 15 minutes and it was still acting the same. I'm having a Ford rep look at it again while I have it on the computer on Friday.....anyone else have any ideas???

 

O.k. fellas, here's the official update.............The Ford rep and I looked over the van again and by now it was barely running. Of course this fellow thinks all techs are stupid and has decided for me that I probably have an intermittant problem with the brain.......and if that doesn't fix it then we'll replace this or that until we get the problem........I decided that was not the way to go..........try telling the customer that he has a $3000 for replaced parts. The Ford rep insisted that it could NOT be an exhaust problem because there was adequet airflow out the tailpipe and it had passed the emissions test only a month ago. Before I replaced anything else, I waited until the factory rep was at lunch and I took the O2 sensor and air tubes out. Guess what????It runs like nobody's business!!!!!!!! Looks like the catalytic is clogged or a baffle broke off in the muffler....I opened the exhaust and put the rest back together and surprise......IT RUNS GREAT!!!!!!!!! I suggest that all you mechanics out there check the catalytic first if you are experiencing the symptoms that this van has been.....Just like I always tell younger mechanics......your first hunch is usually right.Funny thing.I had another vehicle come in today with the same problems.....I think that since the government is fooling around with grain gasoline again we are going to see a lot of odd fuel/exhaust related problems.Oh ........the Ford rep was on the phone later on telling several of his dealerships with troubled vehicles that HE found the problem.....check the exhaust systems......what would we do without these intelligent fellas?????????lol

 

Lack of power after warming up usually indicated a restricted exhaust, the cats don't last forever, so I'd say replace the 2 with a single aftermarket, and put a decent exhaust system one.. If you can find one I'd use a dual in dual out cat, and put duals on the van.