I have a '96 Ford Ranger 6 cyl. and I've had quite a bit of work done on it since I bought it last fall and have put very few miles on it. I just had performance check done and they replaced the spark plugs and recommend I clean the fuel thing and the mass air flow (whatever that is). I pointed out that they cleaned the fuel thing last time it was in (they have a big sign there at Canadian Tire, No Extra or Unauthorized work done" lol) when I pointed that out they told me they always recommend that or something. I didn't have it done. Now, after only about 50 kilometres (I barely use the truck, I prefer my Sierra) I went to get coffee and the engine clicks then revs up a bit. Slowly revs down, then clicks and revs up again... It revs up about 4,000 rpms if that gauge is any accurate. Could this be related to the work they already did or something new?