Pls if anyone has experienced such before. Pls what can I do to get a permanent solution.

Seems your engine has been compromised or its weak and needs to be ringed. Try and get a good volvo mechanic. If you reside in lagos, there are many volvo mechanics along capitol road, Agege.

My honda accord 2003 recently had a similar issue, if I hit the breaks hard, the engine looses power and would sometimes go off, problem was a dirty and clogged fuel filter, it was changed and the problem disappeared.

Run a scan also check for vacuum leakages

You may have a vacuum leak to the brake booster plus dirty throttle body.

Check to see if brake booster hose is still connected, the run the engine, spray some soapy water on the vacuum hoses and look for leak(you might be able to hear the hissing noise of a air leak too.

There should be a vacuum diagram on your bonnet

Did anyone work on your car recently?

Thanks guys I will make finds on the suggestions

Justdulla:
Seems your engine has been compromised or its weak and needs to be ringed. Try and get a good volvo mechanic. If you reside in lagos, there are many volvo mechanics along capitol road, Agege.

You need to be banned from cartalk section, no offence

Taolakprinting:
Pls if anyone has experienced such before. Pls what can I do to get a permanent solution.

You likely have an issue with your fuel system, fuel pump, filter, nozzle and co. Get those checked out first. Tnx