@Ian1892 I thought this sounded turbo'ish... I had to replace the valve cover assembly on mine, there was a built in check valve which failed. Does it run well at speed and have trouble at idle, low speed and acceleration? all signs of an air leak, any number of possible sources for it. need to eliminate them one by one. pop the hood and listen for a telltale hiss.
@JimboSaturn its happened to me several times over the years, only my last 2 cars have been bought new I've had alot of tempramental hard driven used cars (pics upon request)
You need to get your throttle body cleaned. They get really dirty on the inside and will cause that, had it happen and i cleaned it. Ran like new again.
@Sojournersoul Throttle bodies can get dirty - I had the one on my Mazda (2.0 V6) cleaned up once and it improved the drive. Also worth checking are induction leaks - I had a problem with a bit of plastic trunking splitting, and this made the car impossible to drive smoothy at low speeds.
On this engine it's the plastic hose with the 'concertina' in it, between the air cleaner and the induction manifold. and, cruciually, after the mass air flow sensor. This might be worth checking for splits.
