Yesterday I posted a thread titled "Rough idle driving me nuts", begging for help with an erratic, rough idle in my 93 5.0. This was due to the fact that I had been battling this problem for about two weeks. I had pulled codes 14 and 19 from the ECU and performed the following actions which did no good: Distributor...replaced TFI...tested-passed IAC...replaced plugs...replaced plug wires...replaced and upgraded (2)o2 sensors...replaced MAF...removed /cleaned EGR valve...removed/cleaned throttle body/EGR spacer...removed/cleaned gaskets for all the above...replaced Timing..set to 12 deg BTDC Spent 300+ bucks and over 12 hours before I gave up and drove it 60 miles north to an old friend who owns a mechanic shop. Turns out the codes were actually 41 and 91...and the whole problem, (even the cause of the lean o2 condition), was a split vacuum line way up under the upper plenum!!!!!!! I AM SO STUPID!!! I guess it's true -- when all else fails...go back to the basics! BTW, Thanks White 95 5.0 for your help!