Cruise

Cut the leads of your snap on jump pack, put eyelet terminals on them, get a decent size car battery and drill and thread the terminals 6mm. Bolt the two leads to the appropriate terminals on the battery. Best jump pack you will ever have and cost less than £80

Sounds more like an air leak on the intake manifold somewhere. Squirt a bit of brake cleaner around the intake manifold and see if it makes the engine note change, if the engine suddenly changes note then you have an air leak creating a lean mixture. The engine light will not reappear immediately following being cleared, it will monitor the lambda for a number of miles and then throw the light back on once it has determined it is still running lean. Hope this helps

I Second the Autel, excellent bit of kit and good value for money