Two weeks ago as I left to head for a 3 hour trip only for my car to idle hunt at the first traffic light and the same on first gear when my foot off the accelerator. It also was taking its time to drop the rpms when my foot on the clutch and it was back firing when changing gears. I tried not to use the car while there and only tested it for the next couple of days where the problem seemed intermittent. Drove it back and had a BSH PCV fix waiting for me in the mailbox. Replaced the PCV and went for a spin and all felt ok.
I also ran a fault check via vcds and found that all cylinders misfired during the 3 days I was away (different times). I cleared the faults and went for a spin and all was clear when i did another fault test check.
However its never that easy. The car feels it's lacking boost and it comes on late. While it idles ok, its not perfect. I can still feel slight vibration in idle and sometimes it drops rpms (by about 100) and also sometimes hold revs before dropping while changing gears. Also sometimes the engine sounds a bit harsh and yesterday I heard a fairly loud backfiring from the exhaust when revved it to 5K at home (car stationary). I suspected the DV so pulled it out yesterday and had a look. Its a Rev G and it looked in really good condition, no diaphragm tear and felt ok when pressed on the seat.
Which leaves me with the MAF, that I will be testing tonight by unplugging it and going for a run. If it is the MAF, then is it possible for it to foul or fail at the same time as the PCV or is there some sort of r'ship between the two? should I try to clean it and how would I go about doing that?
Maybe there is a air/vac leak somehwere?
I'm running Forge Twintake, Miltek TBE resonated, APR Stage 2.
Any help or thoughts would be very much appreciated