Since I installed my headers(3 months ago). I've been pulling a egr code. I already posted this in tech twice in tech as well as a local message board and nobody can tell me what it is. The code is p400f, I took a full scanner and scanned and under egr it read 0 percent? The car idles fine so I'm sure it's closed, but I can't see anything cause it's on the back of the intake manifold. How does the computer control the operation of this valve? Maybe a connection came undone, but I can's see anything.
Thanks brad
P.S. it's a 97 lt-1