Best OBD II scanner, P0193 code
 

I've got a 2007 Mustang with the 4.0, as well as my DD which is a '03 S'crew with the 4.6. Both are (unfortunately) showing SES and I'm tired of going to AutoZone to get them to give me the codes. What do folks here recommend as a good OBD II scanner for capturing faults and general shade-tree type mechanic work? I'm sure I could spend a lot of money, but would like to keep it reasonable.

FYI - the P0193 code is currently my problem on the 4.0. AZ says this could be the fuel pump, pressure regulator or pressure sensor. Any advice on which is most likely to be the problem?

Fuel filter
 

Just an update on this thread - replacing the fuel filter appears to have cleared up the problem. I also put a can of SeaFoam in the tank at the last fill-up, but I really think the filter did the trick.

Still looking for recommendations on OBD-II scanners...

Fuel pressure?
 

Spoke too soon. The CEL/SES light came on again last night... on to the next step. It's so intermittent, I don't think putting a pressure gauge on the fuel line is going to help. Anyone here done that? Don't see an easy way to get a pressure reading without cutting into the existing fuel line.

Does the fuel rail have a Schrader valve on it like most of Ford's fuel injected engines? If so, that's where you could attach a fuel pressure gauge.

However, usually if the fuel pressure is low, you will also get other problems, like engine running weak or knocking. I would check that sensor, if possible.

Can't find shrader valve
 

First thing I looked for was a shrader valve. I have a fuel pressure gauge that I can use for that exact configuration, but I could not see one on this engine.

Hate throwing parts at a problem - the filter I could rationalize because it's a service item. This is where I feel like I may waste $70-120 depending on where I get it. If it's the pump, then this will be a waste of money. Have sensed some slight shudders on a couple of occasions, but I was under the impression that a pump either runs or it doesn't.

I had some fuel system problems as well.

The pump that went out on me was making irregular whining noises long before it died. It sounded like a bearing going out on it electric motor. But on the night it died, I did notice that the engine was knocking more than usual. Up to that point, the engine seemed to run normally. The replacement pump had a steady hum, and was a lot quieter than the old pump when it was dying.

I had a new fuel filter that failed very soon after I installed it. The symptoms were similar to yours; shuddering, then the engine just lost power. It was triggered by going over bumps in the road. So I think it must have had either some loose parts or dirt inside that would plug up the flow path when shaken by a road bump. If I stop the engine, it seemed that whatever plugged it up would fall out, and the engine would run normally for a while, until just the right bump would cause the same problem again.

I do not have any experience with scanners, so can't recommend anything.