I guess this is aimed at Robmack and/or charlie99 because my analogue circuit design skills died about the same time as CP/M diappeared. What I'm thinking along the lines of is an adjustable oscillator driven by something such as a 555 and having a beefy enough output stage to be able to switch a fuel injector (2N3055 or similar? IIRC that was capable of switching three amps). The switching rate could be adjustable for between say 10ms and 500ms? This would allow the poor sucker person who is trying to clean their fuel injectors to concentrate on maintaining a steady input pressure with the carb cleaner. I really needed three hands for this job today, instead of two hands and an elbow. Hitting yourself with a steady stream of carb cleaner gets wearing really fast.

The design you're looking for is published by Dinofab.  It's a dual 555 based circuit with adjustable frequency as you desire as well as monostable operation which fires the injectors for a fixed duration.  I've a board designed for this project but never got beyond the prototype stage.

yeah we did that already dai

you didn't see albys ic3000 ?

I also have an adjustable frequency one here also

still crudely just a pc board and some cables ...but it works

back with pics in a sec

heres robmacs addition to a thread

https://www.k100-forum.com/t3024-cleaning-fuel-injectors#31050

and albys ic 3000

https://www.k100-forum.com/t3111-introducing-the-k-ic3000

and my injector sequencer - pulser

Well, that really will teach me to run a proper forum search first . Many thanks gents - I think I'm going for the Dinofab one.