Summary: Driving to work, car is revving OK. Boost gauge (both of them) starts to climb at normal revs, but slowly, but the car has absolutley no go, until suddenly it surges forward, and needle shoots up on the boost gauge.
Symptoms: Just before it surges forward, can feel a grumble/rumble from the prop shaft like it is stuttering, then it surges, but the rev counter doesn't stumble at all, either holds steady or climbs as you would expect.
Does this sound like clutch, or engine mechanicals? Clutch action doesn't feel any heavier, and the bite point doesn't feel any higher.
Clutch was changed at 80k by a previous owner, car now has 144k on it, still idles and normally drives smoothly until this morning.
Since I've had the car it has been running sweet. I've changed the plugs, fuel filter, leads, cap and rotor, Lambda and thermostat and it has just had it's third oil and filter change.
Some background: Think I may have a hole in the exhaust (probably the flexi) as it seems rougher sounding the last week. Would seem to be confirmed because after oil change Tuesday night, when I started it Wednesday morning, there was a plume of white smoke (thicker and smellier than normal condensation), it cleared in about 20 seconds, didn't return. Thursday morning, there was nothing. started as normal, but little smoke/steam even though it was as cold and dry.
Thursday night, degreased the sump/downpipe/lower block area with gunk and a normal garden pressure hose. Friday morning, some steam/smoke but smelt chemically, not oily, again cleared really quickly.
Thinking oil spillage, or the degreaser washoff has run into the system, settled and burnt off.
I have a blown exhaust manifold gasket that seals itself after a few minutes gentle heating/driving, and I think the CAT is shagged, because when booting it, I hear what sounds like a slightly tinny but very quite noise sounds to be directly below the brake pedal and slightly infront, which I think might be the innards of the CAT broken up and blowing arround.
I'm going for one of those Ebay Mongoose systems, and thinking about a downpipe (CAT not needed on a car this age in the UK) to sort the exhaust and CAT problems, but do you ready the lack of motion v revs to be a clutch problem?
Need to get this sorted as the car is a daily motorway driver, and I need to book time off to get it fixed.