I have recently starting having multiple problems with my 01 4x4 blazer. It's giving multiple codes p0300,p0327,p0341,p0446,p1415. I have changed the motor out from a 97 Jimmy so the knock sensor was the old style and I never hooked it up to the motor I just put it on a stud on the firewall to give it a ground so I know that's an issue that's causing one of my problems, but that's not the reason for the post. What I need to know is my vacuum issues first. There's a vac line coming off the sec. Inj. Pump that goes somewhere and can't figure that out. Then I replaced the vac line that goes from the tee by the brake booster to the trans and the one that goes to the 4x4 act.switch and now there's the one that says goes to the atmosphere has a big hole but has been hanging there since the motor swap. But ever since I changed those two hoses my speedometer won't work until I get to 20mph and it slips in and out of gear while I'm going down the road like it's really low on fluid or something which I'm not just replaced the fluid and filter. I'm just looking for some help on the vacuum/shifting issue I'm getting the other sensor issue resolved when funds come available.