Hi all,
I have a 1996 E350 with a 7.5 engine E3OD automatic.
Lately after my son has been driving for about 1/2 hour the truck seems to loose all power and max speed is about 60 KPH (40 MPH). It is almost like limp mode. He stoppped and checked tranny and it was down a bit (1/2 litre), after topping it up the truck worked fine for a couple weeks. Last week same thing happened again only this time tranny needed whole litre and was again fine. Then on Monday it did it again and tranny is full (in fact a bit over). He brought the truck home (limpoed it in)) said that the check engine light had come on as well and that it seemed to feel like it was running on only half the cylinders and that he stopped and put it in park and tried to rev the engine but it didn't rev up only seemed to be starving. I went out and it fired right up, no eng light and lots of power. I drove it around for about 20 minutes with no problems. I replaced the fuel pump last fall and new plugs etc in Dec. I was wondering if anyone has experienced anything like this before, I hate intermitent problems, perhaps a sensor going or bad ground that works loose and then is good again.
Any help appreciated.
Thanks

 

First thing is to check the codes. Look in the tech articles there should be one about doing just that. The computer will tell you what is wrong, you just have to ask it. It sounds like the icm is bad, or a clogged cat. It's also possible the spout connector is loose or fallen out.

 

The check engine light is not on anymore, only came on the once. Does the computer store the codes even if light not on?

 

Where is the spout connector located so I can see if it is loose.
Thanks, some good start points

 

i was gonna say check the cat by banging on it with your hand and if you hear things banging around it is all broken up...on my 460 the power would be really bad at times and if i hit a bump or shut it off the cat would open up again

 

Mooner, you ICM (Igntion Control Module) should be on the drivers side fender, behind the battery. The SPOUT connecter should be right close to it. It's just a shunt in a wire that makes or breaks connection with the timing advance/retard signal from the computer. And YES every time the CEL comes on a code is stored. Some codes won't turn it on, but will stay in memory. The GOOD way to check the cat is to pull the exhaust off at the manifolds and fire it up. If it smooths out and runs fine then there is a restriction in the system. Then hook it back up and pull the muffler off first. It's cheaper (at $20) than the cat (at ~$100)...

 

Well I changed the exhaust (muffler was shot) went to 3" from cross pipe all the way using a 3" in/out muffler. The CAT had been removed prior to my getting vehicle two years ago so didn't bother with that. The truck worked great for the past 3-400 miles then the thing started acting up again. Lost all power and it started to backfire slightly. The check engine light would come on for a bit then go out for several miles then on again. This continued till we limped home at 30 MPH top speed. I was thinking perhaps the O2 sensor could be bad but then why is it an intermitent problem. Also is there a way to get codes without purchasing a reader ($250 cdn). I know on my old Dodge(sorry for swearing) that if you cycled the key you got the codes from eng light flashing.
I checked wiring to spout connector etc and found all good. Any other ideas, this is starting to gropw tiresome as I need truck (18 ft cube van) for work and must be reliable.
Thanks

 

People, youare speculating a lot here. Yes, the computer stores the codes. Check them, and then we can proceed.

 

How about the timing chain? Is it worn out so much that it is jumping time? How about the distributor gear/ bushings also? Have you looked at the wires,distributor cap and rotor? How is their condition? Fuel filter clogged? Just some thoughts...... Good luck and let us know what happens. John

 

Good point about the fuel filter! I forgot all about this until reading your post, but I had this very thing happen to me several years ago. I would be cruising down the freeway when the check engine light would come on and the engine would go into limp mode for a while. I'd slow down and it would clear itself up, and off we'd go again. Drove me nuts for a couple of months until it came up on the filter change interval. When I pulled the filter it released some real gunk (I must have had some bad gas). A new filter and it never happened again.

 

Good. A little maintenence goes a long way. Next time this happens, you will know exactly what the cause is. However, if that check engine light came on, I'd still go ahead and pull the codes, as they are still in your computers memory.