Hi all. really appreciate this site. For intro's, I cut my teeth in the early 60's on GE turbines,Lycoming apposed 6's, and Pratt&Whittney radials-1800's-2800's and the really big mothers with twin turbos the size of small garbage cans, all thanks to Uncle Sam. My total rebuilds have been mostly detroit iron,with the exception of a couple of VW,s. I guess at 60 we turn stupid. I rescued a dead '88 740 b230f from the boneyard to replace my beloved '85 caddy.

Situation so far brought it to life, thanks to your FAQ's, with a rebuilt distributer and Huco ign amp [power stage--whatever] Replaced as out of specs or unreliable following items alt amm ect sensor knock sensor coil
plug and coil wires ox sensor fpr fp check valve and filter.

Did the whole tb-intake man-oil trap-flame trap-tps and iac thing. Had the injectors cleaned and tested. Set timing and idle speed [ after replacing crank gear with broken tab and worn index tang, as well as slipping db crank pully].

Cleaned and tested all grounds, batt and alt connections, engine compartment connectors,[harness and sensor] Performed all tests I could find at ecu and icu connectors, power stage, amm, hall effect, tps etc-etc-etc. compression is 152 across the board. valve lash is withih specs & cam shows no wear. No vacuum leaks [tested with propane, light oil,carb cleaner, and stethascope. No exhaust leaks. fp's both working, fuel preasure and flow ok at all rpm.

problem is [at last you say] a random rolling miss that starts about 1900rpm and intensifies to a fullblown hairball at 2900-3000. It does exactly the same with any combination of two ecu's [one a rebuilt] and 3 icu's [all used]. Tach with inductive pickup shows plugs all firing--- but tach will jump higher each time it occurs, more so on #3&4. timing light with inductive pickup shows steady advance until hairball and then just wavers-no definate step retardation to indicate knock sensor coming into play.

Well Ladies chew on that a while and let me know what you think. Thanks ahead of time.
RJ