'94 2500 Suddenly Gutless

[mutagen]

I've got a 94 with the 305 in it. It has 270,000 miles but has been running strong for the last year and a half I've had it. I changed plugs, wires, cap and rotor a few weeks back and it passed smog well under limits.

Yesterday my buddy changed the oil & brake pads for me. Driving home from work it was running fine. Later on last night it took way to long to start and when it finally started it was idling rough but ran fine. Now this morning it is gutless and running a little rough at just about any RPM. It didn't get any better on the way to work.

I gave my buddy hell about it but he swears he touched nothing. Oil is still in the engine and nothing looks obviously wrong.

Any ideas?

One suggestion was EGR valve. How can I check that out?

[mutagen]

How about a clogged injector?

I pulled the air cleaner cover and gave the throttle a little push and only one side has gas, the other side is dry.

Now, anything I can do easily to clean that thing?