Since the cylinders are leaning out under boost air leaks are less of an issue. My guess is some kind of quirk causing cylinders 1 & 2 injectors to be metering less fuel than required. I would swap them around to see if the problem moves or measure them somehow against the others to be sure they are balanced against the others. Depending on the system they may be indidually calibrated so you can put more or less in each cylinder by modifying the fuel map. Pulling the spark plugs will confirm that the cylinders are running lean. Meausuring EGT from each cylinder is another way to tell. Before running the motor again I would do a compression test and leak-down test to make sure each cylinder is working and there is no damage. I would not suspect an ignition timing problem since the other cylinders seem to be running alright. I would recheck that there is no mistake with the firing order and that the wires are not cross-firing between 1 & 2. David Teitelbaum vin 10757 --- In dmcnews@xxxxxxxxxxxxxxx, Martin Gutkowski - DMC Ltd <martin@...> wrote: > > Nick is running an EFI/Electronic ignition setup that means that air > leaks are a moot point unless huge because he is running speed density > metering. Ditto distributor mods - he isn't running mechanical timing. > To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/dmcnews/join (Yahoo! ID required) <*> To change settings via email: mailto:dmcnews-digest@xxxxxxxxxxxxxxx mailto:dmcnews-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/