Recently purchased, always ran fine. Today I started it, it was like it was running on 2-3 cylinders only, barely able to stay alive. Turned it off, started, and it ran perfectly. And has run perfectly since (5 starts). Any ideas for this on/off problem?

 

I guess my question is, what are the touchpoints that control only half the cylinders? Relays etc?

 

The 1 to 6 cylinders get the fuel and then the separate wires for the ignition both from a source , one source for each , these sources have splices and a splice can be bad

So background , the ignition " power " to the coils " sitting " on them present at all times waiting for an ECU provided ground to have current run through the devices to do their thing , either make the coil energize and zip the spark plug or as a totally separate wire system open the fuel injectors

So the splices located on top of engine under the 4 inch wide Jaguar labeled cover

The power for the coils starts at X

The power for the injectors start at Y

Editing

This diagram for the supercharged engine is the exact same for the normally aspirated except SC does not have a Z device ( EGR to help pass emissions ), only difference is how to regulate the engine with different paramotors like compression ratio ( supercharged shorter stoke on the crankshaft throws ) so the ECU has different data maps determining how much fuel to inject

Editing

 

I tried to get editing done but computer glitch so failed but will try again in morning , sleep priorities as father just died

 

The wiring guide is not physically correct but is functionally correct as that many wires should not be placed in a single splice for general practice reasons and how much space you have to place a giant splice , so that single splice item becomes 3 or 4

From reading others these splices rarely go bad but doesn't mean they can't

 

The blue wires same thing for the coils ( fuse # 12 right engine bay fuse box ) , gotta go and focus on my night meds accomplished and get some sleep to do tomorrow

But the writing of this reply and it's technical aspect does relax me