Grand Marquis and p71 engine swap

Crown Vicman

Junior Member
Hello how are yall doing, good I hope. I helped a friend put an 06 grand Marquis motor in a 03 p71. The motor only has 80,000 miles on it. I have know idea whats going on but the car runs rough and smokes bad like its getting too much gas. The car idles too high as well. Not sure if his throttle body is bad or maybe he needs the computer from the 06. We had to swapp over his throttle body because the newer cars are electronically controlled. Any help will be greatly appreciated.
 
Why Did you swap the wiring harness? Why couldn't you just reuse the 03 stuff? I know you said the "sockets" were different. which parts?

Something I learned years back when it came to engine swaps. Anything Mechanical goes to the new car, anything electrical stays with the old car.

from the 06 you should have used the following, basic long block, intake. Then you reuse the 03 fuel rails, injectors, plenum and throttle body, egr, TPS, and other related sensors.
Though some of the electronics may have changed, as far as I know mechanically the 4.6 didn't.
 
^^^^ +1 on everything posted above

With that said you may have a stuck open injector. You should read the codes.
 
Why Did you swap the wiring harness? Why couldn't you just reuse the 03 stuff? I know you said the "sockets" were different. which parts?

Something I learned years back when it came to engine swaps. Anything Mechanical goes to the new car, anything electrical stays with the old car.

from the 06 you should have used the following, basic long block, intake. Then you reuse the 03 fuel rails, injectors, plenum and throttle body, egr, TPS, and other related sensors.
Though some of the electronics may have changed, as far as I know mechanically the 4.6 didn't.

^^^this^^^!!!!
 
Found out an injector plug wasn't pushed all the way in and that we were losing vaccuum. The car is running great now. I would like to say Thanks guys and I really appreciate all of your input.
 
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