So I've been playing with the 95 e250 with a 4.9 with E4od. It has 122k miles on it. I originally had a miss at idle and a 411 code. Those have gone away but every now and then I'll get a CM 212 code that pops up on the reader. However what still persists is that I have a hesitation when I put it in drive or reverse. It will idle and rev up fine in park or neutral. It will idle fine in gear if I don't take my foot off the brake. It's only when I start to roll or slightly apply the gas that it starts to want to stall/buck. Seems like it does it more slightly in reverse than drive. However, once you get past roughly 4mph it doesn't do it and seems to drive fine. Current possible things I still need to fix is Maybe this 212 code that sometimes randomly pops up. The brakes feel good except that the pedal goes almost to the floor before it grabs. They don't feel spongy like there's a bunch of air in them. Just feel like there's way too much play.

I've checked the timing
Replaced:
Plugs
Wires
Airfilter
Rear end speed sensor (speedo was jumping all over the place) Haven't checked to see if that's fixed after replacing yet.
Fuel pump ( had low pressure to start with)
Fuel Filter
Throttle body gasket
IAC
TPS
Throttle Body (my set screw was messed with so replaced it with one from a junkyard)
I've tried 2 other PCMs from the junk yard when I had the 411 code and none seem to change
Swapped out solenoids from the junkyard (the three that on next to each other on the rear driver side of the engine)
Swapped out 2 different black box ICM from the junkyard
Replaced any bad looking vacuum lines
Cleaned up any grounds that I could find
Hooked up a vacuum gauge to the FPR and it held vacuum.
Hooked up smoke to the brake booster line and didn't notice and smoke coming out of where it shouldn't (guessing is supposed to out of the black **** on the IAC)
Compression check all cylinders 145-150psi
Timing is right at 10

I didn't really want to do it but I almost want to take the intake off and replace the gaskets and FPR and fuel injectors as both of those are a pain and check the vacuum lines that run under it.

Unless anyone else has an idea I should be pointed to. I was told the CAP and Rotor were replaced by the school district right before it was taken out of service since they couldn't figure out the problem. It does look new however they said all parts they replace are OEM and pretty much everything I found that was replaced, wasn't OEM. I'm sure I'm missing something I've done or tested.

Any ideas?

 

And unplugging the green line from the EGR doesn't change anything.

 

If you've replaced all that and checked hoses I'd bet its one hidden or a slight intake leak.

 

Thanks for the response. I'll probably just do the intake gaskets since I have them and can check that off the list.

 

So I decided to hook up a vacuum gauge before tearing into the intake for a leak. It reads around 23-24 at the high end of the green zone in park. Step on the gas and drops to very little and back up past the green then drops back into the green as it should be. However I put my foot on the brake and put it into D or R the vacuum starts reading 16. Right in the red zone that states lateing timing on the gauge. Take my foot off the brake and it will hesitate and when it does the gauge goes down to almost nothing as the rpms drop and then back up to 15-16. So since the gauge is staying put in the "lateing time" should I still be looking for a vacuum leak or should I be focusing on timing now? Not sure if a vacuum leak would be that consistent or not when I put it in gear.
Thanks

 

Disconnect the brake booster and try it again. Cycle through drive and reverse. You may have a leak in the booster that only appears when you press the pedal. I've not dealt with that enough to know if a brake booster could effect vacuum.

 

It does still do it with booster disconnected. And it also does it when I put it in gear but continues with low vacuum after I release the brake as well. Thats when the hesitation/ bucking starts. Thanks for the response.

 

SOLVED: I just wanted to post this here since this is a common issue with lots of possible solutions as it seemed when I searched. I finally figured out the problems so I just wanted to let people know what I found so they may not have to go through the same headache I went through. My main problem with the bucking/hesitation when I put it in drive or reverse ended up being the PSOM unit. The yellow capacitor had come loose on one joint. I simply reconnected it and fix my main issue. Someone in another forum that I found in 2004 said to simply disconnect the PSOM from the back of the cluster and see if the problem continues. If it doesn't obviously this is probably your issue as in my case.
If I remember right I sometimes had gotten a 213 code. I ended up swapping the ICM from a junkyard part and it worked fine. The symptoms were missing. I only noticed it after I fixed the PSOM unit as they blended into each other.
I was getting a 411 code for a long time. Not sure what ended up fixing that as it seemed like it came back every now and then after fixing it all but haven't gotten it for a while now.

Another issue I think I had was my fuel regulator and maybe my pump. I can't say for sure since I was using a harbor freight testing gauge that turned out to be bad. I am pretty sure at least my FPR was bad.

Last issue was my brake booster. It held vacuum fine. But I could hear a swooshing noise when I pressed on the peddle. The brake would feel pretty good and stopped but would go too far in. I replaced the booster and the problem went away.

Anyways I just wanted to update this thread in case anyone in the future has my same problem and maybe this might help them.
Thanks for the help everyone.