Green01

new fuel and air filter, minimal change. was removing leads 1 by 1 today and found 1 that had no affect on or off but was producing good spark, but at the next rough cycle when i removed the same lead there was a drop in revs but then a different lead removed would have no affect. What's going on??

G'day from Gold Coast, Australia, Bought '01 ST Pathfinder for a grand, as is, about a month ago. Couple bumps but fairly good condition, 240000km, drive pretty good besides an issue which seams like a misfire, all electrics inside work. Cleaned half of Fraser out from around the motor, changed plugs, oil, swapped out leaking steering rack, got her on the road. Found more sand in the airbox, will be giving the throttle body a clean when i get the time. Wheel alignment in the next week or 2. Im keen to get this misfire type issue sorted, idles fine for 20 seconds then revs drop and she's rough as guts for 10 seconds, revs come good again for about 20seconds and revs drop for 10 and repeat. If i accelerate in Park(30%) it seems a bit restricted but smooth up to 3500rpm then sticks there for about 5 seconds then it zips up to 4000+ like theres no problem. It behaves very similar while driving. Feels sort of like the handbrake is half engaged til 3500rpm, few seconds later its like releasing the handbrake and she goes. I've replaced all the small vacuum hoses as they were old and perished, but no change. I tested the TPS with multimeter, values are as they should b, signal values increase smooth while slowly opening the throttle. seams fine. Any one have any trouble shooting ideas to eliminate or narrow down the possible cause, budget is pretty tight atm but ill be getting some fresh fluids leads filters etc. into her soon as i can. I saw the Fuel filter pretty old n rusty looking today. Anyway, any help would be appreciated, Cheers