94 250 Ram Van 318 ci. 150,000 miles runs smooth for about 10 miles or so then starts missing for about 10 miles or so then runs smooth again or vice-versa. Replaced the O2 sensor - check engine light went out but still have the miss problem. Changed plugs and all plugs looked a tan color meaning to be burning correctly I guess? One vehicle family. Any help at all would be very much appreciated!

 

What do you have for fuel pressure?

 

Had a friend check and said fuel pressure was 38. I drove it across town about 30 miles and it ran fine, let it sit for about 3 hours. Started it up and it was missing. After about 10 miles it was running fine again. Even when it's missing it will accellerate ok. At one time it felt like it was missing on more than one cylinder, vibrating the van and then started running fine the rest of the way back. Lots of rust underneath. Could it be as simple as a ground wire?

 

Makes me wonder if you have an injector that is not working correctly all the time.

Jason