Yes there could be an air leak.
Check the gasket at the rear of the engine for leaks, and the coupling between the header and pipe as well.
Are you using the HPI ribbed pipe? They are extremely loud, too loud in my opinion.
Have you changed the glow plug? It may not be working well, or the wrong heat range.
Is the air filter clean? A dirty filter reduces air flowing into the engine.
Check the fuel and exhaust pressure lines for cracks and splits also.
Is the glow igniter fully chargeed?
A few things for you to check, good luck