Van misfiring... Need help
 

I recently bought a 1993 Dodge Ram 250 Van (318) https://cimg1.ibsrv.net/gimg/dodgefo...29a20b70a9.jpg
with about 200,000 km's on it. Everything works really well in it but once I get it over 90km/hr it has a slight engine stutter. Like it's mis-firing. Accelerates fine & decelerates fine but when I level off and cruise at 100km/hr or so I get a stutter in the engine. I've replaced the plugs and wires thinking that was the problem, but it wasn't. The van had sat for a couple years so I filled it with premium fuel & put some fuel conditioner & injector cleaner in it also. Any other advise on what else I can look at to fix the problem? I've put about 500kms on it since I bought it and seems to be ok. More annoying than anything... Would just like to get it running properly.

The fuel pump could be failing and is not able to deliver the higher rate of fuel needed at the higher speed. Does it also lose power going up hills?

If anything, the stutter happens when I slightly let off the throttle when going down hills. If I'm putting the pedal to the floor and accelerating, it seems to run better/doesn't miss.

Either a vacuum leak, (intake plenum gasket?) or maybe a marginal crank sensor.

That symptom is a sign of dirty injectors. Taking your foot off the gas closes them down to the point where fuel doesn't flow.

He Bent: Neil from Calgary here. Here is my problem. sounds like yours:

I have a 1989 B250 Van with 318 motor, no AC. On recent trips it has suddenly started running very rough, then it clears itself. On the most recent trip it ran fine forn1.5 hours, bobbled a few times, then ran fine again until the 3 hour mark. Then it really ran rough for a while. It feels like a misfire or lack of fuel. But then if clears and runs fine. I have recently replaced the spark plugs, coil, spark plug wires. Hall Effect Sensor replaced a couple of years go. Check Engine codes are 12 (disconnected the battery a few weeks ago), 26 and 33. Anyone got any suggestions?

Did replacing or cleaning the fuel injectors help?