engine sounds different since battery change

[vonders]

Hi there. My boxster '97 was sounding fine, no ticking, until the battery died and was replaced with a new one. Oil levels all good and no other change made. Now when it starts it sounds really growly, which initially I thought sounded kinda cool, but at idle there is a rapid ticking noise, and in between the ticks a kind of scrapey, chainy noise. It doesn't sound good, and on revs it will sound fluttery, and will take a split second to engage power. It sounds like there's possibly more than one issue here. Thinking maybe the battery reset has cleared the engine settings and the sensors aren't supplying the right info and/or mechanical engine/exhaust issue. 87000 miles, drove 83 miles since battery change. The scrapey sound between the ticks is getting worse. Not gonna drive it now if I can help it and get it looked at

[Steve Tinker]

Try resetting the ECU base parameters..
1) Disconnect battery again after removing ignition key.
2) After reconnecting battery, put key to IGN so dash lights up - but don't start engine.
3) Leave in this position for ~60 seconds.
4) Switch off ignition and remove key for ~ 10 seconds.
5) Start car as normal - the base parameters should have been reset.
If problems still persist, hook up a code reader (Durametric or equivalent) and trace fault.