I pulled the intake plenum off on my 97 f150 4.2l because it had set the 0171 and 0174 codes.after I put in a new gasket and put it all back together it now has diffrent codes,IMRC codes.It runs worse than it ever has now.What did I do wrong and how do I fix it? Do I have to pull the plenum again? The codes indicated it was both runners could I have pulled a vacum line off while installing the plenum?

 

What are the codes?

 

Not sure didn't write them down,I will recheck when I get home.i want to say 1516 and 1517

 

you are on the right track
google is your friend

https://www.google.com/webhp?sourcei...0imrc%20repair

 

Please don't get insulted but you did the work and created a new problem.
Just get back in and find it.
Why would there be an answer here since we did not do the work or know what you did.
Are the levers free to move?
Is all the hardware hooked up etc?
Sensors hooked up?
Good luck.