94 explorer that pings

I have a 94 explorer 4.0 that is pinging under power (most noticable with cruise on and climbing hills) the check engine light cycles on during lengthy hills and then goes off when power backs off.
I checked my self diagnostic (shorting the manual suggested 2 pins on the diagnostic contector) codes and I get 186 (injector timing pulse too wide) which doesn't make sense to me.
I took it to a local repair shop and asked him to put his computer on it and he told me that it returned "No communication" when hooked into the connector right side engine compartment.

Does anyone have any suggestions on how I can reliably troubleshoot this problem?

If it has a Mass Air Flow sensor, try cleaning it with an electrial spray. There are posts on the forums how to do it. Do a search and you will find a lot of info on this subject.