My trucks running so bad.all people I know are just guessing it seems. Motor is rough as all get out on acceleration from a cruising speed. Idles fine. accelerates fine. changed timing gears, carb (4brl Roch) timed it, removed spark advanced distrib.,plugs,wires.It's an '85 1/2 ton 305ci disp. Hoping some fine Chevy guru's experiance can help me.Please!

Jason,

Have you looked at the EGR valve? Suggest you disconnect the EGR vacuum feed line, plug the line and drive the vehicle to see if the performance has changed (improved). What you describe sounds like a typical failed EGR valve.

Oldie
Thanks! I did that and it was noticeably running better (big but here) But it got gradually rougher the longer I drove. Is this to be expected? It also diesles after shutting her off??
I will change the EGR regarless. The vacuum hoses look kinda rough to. I think I'll R&R those while I'm at it.

It sounds to me that the roughness could be a vacuum leak, probably near the intake manifold or carb base.
The dieseling may be another matter, or could be because the extra lean mixture , because of extra air entering the induction system. (IMHO)

Gentelmen
Now that i've found the EGR needs fixing and the hoses need fixing. I can't find replacement hose fittings. The emission hoses the dealers have but not the fittings like the TVS which has like five hoses connected to it. Is there any kind of website or buisnes that sells these fittings or even a complete replacement kit? If the fittings are almost 20 yrs old and rotten on my motor, they're sure to be just as bad from the wreckers.
Thanks again for the advice.

If the fittings are not broken dont need replaceing. Just be careful and gentle when removing the hoses.
Most of the hoses will probably be the same size tube so buy a sufficient length from any part shop, will be cheaper and do the same job as genuine.

Well this is the update.At the back of the intake,just ahead of the distr, was a fitting in the intake.It was loose! I replaced some vac hoses,timed her to 8 deg btdc and drove.Still shook on mild accel.Detached EGR again and drove still shook not as bad.I did test the EGR by feeling diaphram and throttling motor.diaphram did raise but almost unoticeable.EGR bad?I think so.Is this the only problem?I don't think so?Motor also knocks on acceleration from a stop.(like a diesel motor)We're getting there!Thanks for past and future advice.Good bunch a guys

Well wouldn't ya Know it?
Now that racing season's started, a fellow at the track needed a ride in my truck.When that problem it's been having happened, He said"Do that again but don't let up on the throttle and gently push the brake at the same time" and the chugging and shaking stopped! "Your four speed auto tranny's torque converter is locking up" YEAHHHHHHHHHHH!I'm not going Crazy