Volvo v40 starts but gutters out

[DonDryV40]

I have just bought a 1999 Volvo v40 t4 which has 140000 miles in the clock, I knew it would come along with some issues. The exhaust is leaky at the front and it's due in to have that fixed next week but last night it presented a new problem, when I turned the key (having only just stopped the engine a minute prior) it started up to idle and then the revs fell and the engine stopped, if I put my foot on the accelerator it starts fine but I also noticed the revs fell when I turned on the heating full blast. I have put a slightly used general racing air filter into it as I was given it for free and it has been running rich, probably due to the exhaust. I was just wondering if anyone had any idea of the exhaust and this new problem were connected or if it's most likely a separate issue?

Also as a side note I need some advice from Volvo owners as the people around me all have hatchbacks, what's the best ways to maximise power in a t4 and maybe even bringing it up to more power than it would have originally had?

[chomerly]

There could be a range of issues which is causing the cut out but I would consider two options after having the codes read to see what the engine management says.

1) get your alternator checked.
I suspect that it is failing as you stated that the revs drop even further when the heater is on full and my first instinct would be that it is producing enough power to charge the battery to a degree but not to power the whole electrical system.

2) have your battery tested just in case this is playing a factor.
It's quite well known that battery's can make cars behave weirdly but they're one of the last thing thought of.

There are numerous options to boost the power from your T4 but it all comes down to how much you want spend.
A bigger turbo, engine management system mods, exhaust modifications, the list goes on.
One member you could get some advice from on this is MitchBoy01.
He's done a lot of modifications to his motors and can tell you where to look first.

[DonDryV40]

Cheers mate ill have a word with him. Ill have those checked out weird thing is that the engine light isn't on but that could be because the bulbs out, my mate has a code reader so ill plug it in and see what comes up. Doesn't sound like to expensive a problem either way.