I have a 95 F150 with a 4.9L I6 and E4OD tranny. I have had some series problems recently... This past year the E4OD was rebuilt. Just recently I have been working on 2 noises. One noise was a chirping sound coming from the engine which turned out to be the distributor. So the new distributor is in and no more chirping. The other sounds was really scary, it was like a metal grinding squealing noise that would happen from a start and when coming to a stop. It actually turned out to be the transfer case. It was low on oil. I don't think it was severely damaged because once I filled it up with the proper amount of oil I have not heard any more noise from it. I also recently did a tune up and replaced plugs, wires, cap and rotor, air filter, fuel filter, breather filter, belt and a few old vacuum hoses.

Now that I'm through the history... I have a new problem now that I can't figure out. Basically I have a lurch or it almost feels like the engine is about to stall and then doesn't. It only seems to happen when I'm cruising along on the highway at 65-70 and as far as I can tell it's completely random. It doesn't do it very often but it sure gets my attention when it does it. Other than this lurch the truck seems to be running great. Does anyone have any ideas?

 

Is the lurch quite small, almost like it's missing, and sort of hard to put your finger on? At constant speed?

PCV valve, I would bet London to a Brick.

 

Check fuel pressure with a gauge. You can run the gauge out the back of the hood & tuck it under a wiper so you can check it while driving.

Also, get a Haynes & a cheap multimeter, and follow the ignition diagnostic procedure (usually Ch.5 Sec.5). It'll take ~1/2 hour, but it'll find ANY problem in that system if you do it exactly the way it's written. It should even find this, but read this caption anyway.



If all that checks out, I'd dump the rear diff oil & inspect all the gears. Click my black Bronco below & look in the 8.8" Axle album for more info.

 

So far it has been a small lurch almost like a miss. It feels like it just cuts out for a second. I got it to do it the other day when I was going slower and I was accelerating. It felt like the engine just bogged down for a second or two. I did get a brief check engine light also so I'm going to pull codes.

The PCV valve was replaced when I did the tune up. I had forgotten about it. The valve was kind of strange though because it had two vacuum ports and a little plug to block one of them off.

Steve83: I have a Haynes manual and a multimeter so I will give that a try. I will have to borrow a fuel pressure gauge or go buy one.

 

Although Steve83 probably hit it on the head, might i also suggest checking the routing of your new spark plug wires. If not routed properly they can misfire. But definitely do what Steve said (it never hurts to check, it can only help).

 

The I6 isn't nearly as sensitive to plug wire routing as the V8s, but the #1 wire is always pressed against the PS/AC bracket, and it might be leaking spark.