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Hello, thanks for posting
The temp gauge 'jumping around' indicates that this is an electrical issue, hard to determine what it is due to being intermittent, one way to go about this is to try to simulate the condition, start at the fuse box under the hood, while the engine is running wiggle the relays and fuses around, it could be a poor fitting relay or fuse or corrosion on the connectors in the sockets. The EFI relay and engine main relay are a possible source of problems. Move some of the wire harnesses around going into the fuse box. Do the same at fuses inside.
A bad ground or corroded, loose terminal connectors could also cause this. Check the engine ground wire connections, they are all brown /black, let me know how it goes.
Hello, thanks for getting back to me
when it won't start does the engine turn over but not fire up or does it do nothing at all?
Dot the dash lights come n when the key is turned to the on position?
Thanks, ***** ***** cable is it? Positive ot negative? It sounds there may be bad connection between the battery and either the fuse box under the hood or the ground connection, do you happen to have a volt/ohm meter handy?
You may want to have that checked using the testers they have, they'll check the battery and the charging system, it sounds like that's where the problem is, they usually do this at no charge, let me know what they recommend doing.