After repairing two vacuum leaks my 2003 WJ fuel economy increased by 9.4 MPG.
1. The vacuum line was cracked on the cruise control canister located under the battery box. Be careful not to crack the canister nipple (like I did) when you pull the line off. This repair improved both the cruise control acceleration and the AC/heater distribution control and the overall vacuum pressure.
2. The LDP vacuum lines located under the driver sidereal quarter panel were really in bad condition. My mechanic did this repair for me as he had the equipment to command the LDP. It turned out the valve in the LDP was not switching but it was fixed by cleaning it ( I think brake cleaner was used).
3. The pesky engine code 1494 has finally gone away. I hope this post helps some of you that are chasing the vacuum leak problem. Both locations are hard to detect using a homemade smoke tester. A visual inspection is the best method. If you go to the bother of gaining access to both areas you might as well replace the line. I noticed the thickness of the cruise control line was heavier than the normal 1/4 line so I used rubber gas line to replace it.
1. The vacuum line was cracked on the cruise control canister located under the battery box. Be careful not to crack the canister nipple (like I did) when you pull the line off. This repair improved both the cruise control acceleration and the AC/heater distribution control and the overall vacuum pressure.
2. The LDP vacuum lines located under the driver sidereal quarter panel were really in bad condition. My mechanic did this repair for me as he had the equipment to command the LDP. It turned out the valve in the LDP was not switching but it was fixed by cleaning it ( I think brake cleaner was used).
3. The pesky engine code 1494 has finally gone away. I hope this post helps some of you that are chasing the vacuum leak problem. Both locations are hard to detect using a homemade smoke tester. A visual inspection is the best method. If you go to the bother of gaining access to both areas you might as well replace the line. I noticed the thickness of the cruise control line was heavier than the normal 1/4 line so I used rubber gas line to replace it.