Engine pulse while in drive

[98mustanggtkid]

hey all!

So I have a question I recently changed the plenum on my car, its the C&L plenum, I somehow also got shipped on of the spacers that goes between the manifold and the plenum so I put it on. sometimes when I am sitting at a light the car will start to pulse if i give it gas it seems fine. if not all the time just sometimes, do you guys think it could be the new plenum/spacer combo. I had an aftermarket plenum on the car before but when changing the IAC valve i broke a bolt off in it. the only thing different really is the spacer and they type of plenum, it was a Trickflow plenum now its a C&L plenum.

Any help would be awesome!

Thanks!
Chris

 

[vermilion]

any check engine lights yet? i hope you sealed it correctly.

 

[98mustanggtkid]

the only CEL lights are lean banks 1 and 2