R2500 tranny issue

[texcl]

So I just bough a really nice 1991 R2500 sub with a 7.4L. When I picked it up it drove fine no issues what so ever. Well I was on a 200 mile trip last night and at about mile 100 or so the truck started surging at 75mph. If I lowered my speed to 70mph it all but went away and at 65 it was not there at all. I pulled off on an off ramp and wanted to test the transmission function from a stop and sure enough it stumbled when flooring it. So what could cause this to pop up out of nowhere? Thanks in advance!

 

[Greg Ducato]

That sounds more fuel or engine performance related than trans. Check fuel filter, egr , ignition rotor etc

 

[texcl]

That sounds more fuel or engine performance related than trans. Check fuel filter, egr , ignition rotor etc

Yup, it is an engine issue. I can put it in park, get the rmps up and the engine will studder. I checked for codes and there are none. I have an original service manual and it is pretty worthless. Is the distributor similar to a carburetorengine?

 

[Greg Ducato]

It has a conventional cap and rotor and magnetic pickup, any of which can cause this kind of symptom

 

[diesel4me]

If it has a catalitic converter,it might be plugging up inside also..it'll restrict the engines ability to breathe at higher RPMs..also lose power too..

 

[Fordum]

Since it got better at a lower load at first, I'm leaning toward a fuel issue. Sounds like it was not getting enough flow to keep running at 75, but had enough for 65. Plus the surging sounds just like fuel.

I'd start with the fuel filter, but be prepared to drop the tank or put in a door to replace the pump.
Or even easier, try loosening the gas cap for short time to make sure the vent line is not kinked.

 

[texcl]

Pulled the do cap today and all the points were severely corroded, I sanded them down but have big pits. Actually made it run worse,lol.