If driven in a high gear 4th or 5th at light throttle and low rpm (1000-2000) this car starts to hunt. It can be very mild or sometimes gets quite uncomfortable.
The customer has done a fair bit of investigation himself (don't you just love that?) with a new MAF (genuine Siemens), temporarily blanked off the EGR valve to no good effect. Some but not all engine mounts replaced.
No codes stored all live data intially looks good.
I blocked off the vac pipe for the inlet air throttle with no change.
I thought it might be DMF but apparently not fitted to 90's, solid flywheel on these. The clutch however is quite worn.
On roadtest when the symptoms are evident it is possible to see fluctuations of fuel quantity and pressure when graphing live data.
It feels to me that something mechanical is upsetting the stability of the engine management system. Perhaps there is a software upgrade.
Just wondering if anyone has had similar issues with these as there is loads of postings on non-trade forums about similar issues with no resolutions, seems like the answer is put up with it or sell the car.