I have a '95 F-150 with the 5.8L and it has a tendency to hesitate very slightly right immediately following the hit of the throttle sometimes, right before it shifts to overdrive out of fourth if you lift off the throttle a tad bit before shifting, and even while cruising at a steady pace every once in a while. The plugs are a nice cocoa brown, the cap, rotor, plugs, and wires are all new. And there are no visible vacuum hose leaks or deterioration. The truck is very well maintained also. The only thing that comes to mind though, is the PCV valve. It's still stock with 95,xxx miles on the odo. The hesitation is extremely slight and it doesn't even do it all the time, but it's still enough to bother me to death. Anyone else have any recommendation as to where I should poke my head next??? Thanks.

 

maybe throttle position sensor.

 

I have the same problem. New vacuum lines where necessary and new TPS. Still does it exactly the same. Runs perfectly otherwise, even good gas mileage. I got over 14mpg with mixed city/highway with 3.55's and an E4OD. So I think the motor is running right except for that first throttle tip-in hesitation just as you get rolling.

 

You mean you put new vacuum lines and a new tps on the truck and it still does it, or is that the problem? It's really getting on my nerves, haha.

 

I installed a new PCV, EGR, EGR position sensor, TPS, replaced all vacuum lines that didn't test PERFECT, cap, rotor, wires, plugs. I cleaned the TB and IAC up a little but they're not perfect. This could be my problem but with the big air tubes off I can hear the IAC open and close gradually to compensate for the surge (more hiss as the idle drops to admit more air and bring idle back up, and less hiss as the idle is too high). Vaccum readings on the manifold at idle are right around 18, and the needle wiggles + and - 1/2 inch of vacuum.

Now, the hesitation/surging problem was a lot worse before I replaced all of those things, and it's really not bad, but it's annoying. I also have just a little bit of a shudder taking off from a stop, and I have a feeling it's related. If I can get the surge/hesitation thing fixed and it still shudders I know it's my auto transmission slipping. If not, I can't say for sure if it's a engine performance or transmission problem, really frustrating. This is the only shudder I feel, no TC shudder going into lockup in overdrive, etc, like you'd expect.

I got hit with the bright idea of disconnecting and plugging the PCV inlet on the manifold to see if that was causing the problem somehow. Haven't tried it yet.

It does seem like this is a common enough problem on 302/351w that someone would have figured it out by now. Searches turn up the same description over and over.

 

LogicalRetard, do you have an automatic transmission, and if you do, does it shudder just a little after it hesitates? I have an E4OD and I'm blaming the shudder on an engine management problem right now but I'm wondering about the transmission too.

 

I went and got some vacuum line caps, pulled the PCV hose off of the manifold and capped the manifold port.

I put a lot of new stuff on and it helped a lot, mentioned above. I got no codes at all when I was done. I did put a new PCV valve in earlier too.

After capping it off, there is no shudder, no hunt, no hesitation. It runs like a watch now. 165k miles and it runs like I remember my father's new 302 truck running. Perfect.

Give it a try.

The PCV hose is venting to the air, don't cap it off!

 

I have the exact same problem with my '92 4x4 5.8 rebuild. Ran fine for 3000 mi after the rebuild but now hesitates and surges off idle. Replaced TPS, fuel injectors, fuel press reg. and Idle air bypass valve. I too am wondering if it is the tranny. Mine is E4OD also, with 150 K on it. When I hold throttle just off idle when pulling away from a stop, I can get it to keep surging. The only way to stop it is to step on the gas and get it above 1500RPM. Are all the others that are experiencing this problem E4OD equipped or a mix of trannies? It is very frustrating. I can't imagine that the PCV would cause this problem. Since it doesn't happen all the time it it makes it hard to troubleshoot. Any help out there?

 

Just try pulling the PCV hose off and capping the manifold. It definitely helped mine. I guess I still have it but it's definitely less. Once I got to work this morning and the truck had warmed up it was running perfectly, no hesitation, no surge, no shudder. The shudder seems to go hand in hand with the hesitation, so I am leaning towards thinking it's not the transmission.

 

I was also having problems with my 5.8L running slightly rough at idle but seriously hesitating, bucking, and pinging under accelaration at higher speeds. It was so bad , it would make whole truck shudder at highway speeds, causing serious damage down the line.

Initially I didn't know what to make of it and searched the forums and groups. There were two many solutions, such as EGR valves, carbon deposits, mass airflow sensors getting dirty, and many other suggestions.
At the time I didn't have a code reader and tried to clean "the deposits" using techron and seafoam, to remove any carbon deposits in case that was the problem.
Well, that didn't work. I ordered a $40 code reader and while I was waiting I started pricing EGR valve and other components that may have been the problem. Not a rosy picture.

As soon as I got the code reader and plugged itin, it gave me the code #304.That being a cylinder #4 misfire. I had a spark plug tester - a liitle $3 device you install in between the spark plug cable and the plug, it has a light bulb that flashes on every spark. When I tried it on the cylinder it showed a weak spark, compared to the adjacent spark plug cable output. Figured it would be cap and rotor or the spark plug cable. In the end it wasn't an EGR valve, some sensor, injectors, faulty fuel system, vacuum loss, or unverifyible carbon deposits due to cooler/hotter spark plugs but it was a $2 eight month old spark plug cable that was causing all these problems.

I replaced it and now this 351w purrs like a kitten and growls like a lion and hauls.

Hope this will help somebody.