I'm not sure if running a higher concentration of Techron would be either beneficial or harmful. Thing that bothers me is that the injectors are said to have been removed cleaned and inspected, so if that's the case, why even worry about the cleaner? Kind of double-talk to me.
I'm trying to remember now if the 92 CE was CIS injection or SFI injection, do the fuel injectors have seperate steel lines from a fuel distributor, which is CIS, or a long fuel bar over the injectors and an electrical connector to each injector, which is an SFI system, either LH or HFM. If it's LH or HFM, it could be the dreaded bad wiring harness problem.