i just bought this ride an it misses at an idle...but if you pull the accel. up to about 1500 rpms it smooths out....driving down the road it runs fine...just at idle it shakes the whole blazer so bad if feels like its gonna shake apart...i put new plugs in they were bad an it helped some...changed most of the sensors on it ...no change ...i took it to auto zone an they ran a code check an it had some codes i dont remember what they were..but it had to do with high vaccum...he told me he thought the silinoid that pulled the fumes from the fuel tank was stuck open ...i plugged it off...an it made it worse...can anyone help?