bob just a thought...before you pull the injectors, if you have a scope just check they are all getting signal...and good levels of it...

what i am thinking here is if one is not given the design of the manafold it probably gets enough cross talk to work ok under light load, when cold the cold start injector will help... but under WOT their would be VERY littel cross talk due to the airflow....just a thought, and IF you havea scope with an inductive probe at least you can do the test without any diss assembely...might also just be worth pulling the conenctors (electrical) to the injectors and checking for corrosion, re-seatign them and having a little test run...injector seals might be a thought as well, heat wont have done them any good i guess...

engine earth is ALWAYS worth a check of course but im taching my grandmother to suck eggs here...