Hi hoping you can help me out here. My "P" Reg (Old body style) 90 (?95)BHP TDi has had fluctuating power output for a while. problem seems to be worse when engine is warmed up, most noticeable on an up hill road section or when accelerating hard and revs get to 3,0000 or 4,000 rpm depending on gear selected. It seems to choke up like it's cutting back on fuel delivery, after this happens it seems down on power until after I've stopped and the engine is started next time, even after a few minutes just to pop into a shop.
Have tried the following:
Injector clean additive = v slight improvement New Air filter = better low down acceleration New MAF = Just delayed the problem by +/- 500 rpm
Is there an O2/Lambda sensor on these?(if so where is it located) or could it be more serious such as fuel pump? (I hope not!!)
When cold she runs great, but after prolonged 75/80 cruising or an uphill section under power the problem kicks in.
Mick