Vacuum is what controls the MAP so if there is a leak it can cause the MAP readings to be wrong. Easy way to look for a vacuum leak is to GENTLY spray some starting fluid along the hoses and intake and listen for the engine to speed up. Just don't spray a lot at a time, you don't want to have it running along places. It could "find" a leak if it runs to a spot you haven't sprayed yet, then you think the leak is where you just sprayed.
Another way is to spray water around and listen for it to be sucked in, this way works fine as long as you don't drown the engine. An easy test bottle for this is a soda/water bottle with a small hole in the top. Use it like a squirt gun to spray things.
Wednesday, October 11th, 2017 AT 2:12 PM