Hi

I’m new here and hope my english is understandable for you all, I’m a Swiss living in France and France went just to new lockdown.
So I have to fix my Volvo 940 wagon from 1998 myself.

I have a power problem on my motor which is lacking power and is irregularly hesitationg when I accelerate. So I’m looking for the problem... doing that I wanted to retighten the ground cables in the engine bay. ... and I must have overtighten the screw coming out of the firewall next to the motor top - there are two ground cables coming together and tighten behind the top of motor to the firewall.😫😤😳
The bolt coming out the firewall is broken blat on the firewall.
What do you suggest ?
- leave it like that ?? Not important?
- drill a whole into the firewall and insert a new screw (but this means that there is nothing behind firewall I destry when drilling through....???
- attach the double ground cable somewhere else ?
- welding a screw at the same place, but I only have an elecric welder for strong welding, I might well desintegrate the firewall and also the strong current might destroy electric parts on car ???

Please give me advise, thank you very much and long live to Volvo !