My 94 just started running terrible. It was running fine and then while driving it started acting like the timing was way off or there was water in the gas. It did it for a couple of minutes and then ran fine again. I replaced the fuel filter as a precaution and it ran fine for the next two days. This morning it was running fine leaving the house but after about 5 minutes of driving it started doing it again. This time it didn't stop. It's not missing, its more like the timing is off and it's lunging. It will keep running with the RPM's up but will stall under tranny load at idle but wont stall in park or neutral. I'm not sure if I can drive it to the nearest parts store to have the computer read and havent checked the distributer cap or button yet. Not likely to be them since it was intermittent. Any idea's or anyone have a similar problem in the past. Thanks,

 

It might be a fuel pump problem. If you have dual tanks, try to switch to other tank to see if it will change something. Also read the error codes and post them here

 

What was the anser?

 

Try checking fuel pressure...I had a similar problem on my 89 and checked the fuel pressure and I was getting 80-100 lbs of pressure...changed the fuel pressure regulator and now I'm getting the 55 lbs that I'm suppose to get..problem fixed...

 

As the others said, sounds like a fuel pump or fuel regulator or

Pour a can of Sea Foam Motor Treatment into your fuel tank and let the engine idle or drive it if you can, this stuff will remove moisture from the fuel tank and clean the fuel injectors, it is worth a try.

Not likely timing is off, because the 4.9L is gear to gear, with no chain around them.

Hope this helps!