First, I wanted to thank the members of this community for the gold mine of valuable information. I have a '96 LS with 282k which has recently been throwing the P0401 EGR flow insufficient and P0100 MAF sensor circuit malfunction codes. I cleaned the MAF maybe 2 months ago and will give it another cleaning, but an EGR valve stuck open can trick the MAF into throwing that code if I understand correctly. It has a new EGR pipe, and a clean EGR valve as of 6 weeks ago, and the codes just recently appeared, and reappeared after an ECM reset. ECM is rebuilt as well. I assume the EGR is stuck open, so I was thinking it might be the solenoid/VSV but I don't know where it is located on the 96, or if it has a VSV like the earlier 1st Gen models. Anyway I don't think it's the valve itself, seems like it rarely is. Thanks in advance.

 

Is it this VSV? or is this for the Charcoal canister only?

 

That part#
https://www.lexussouthatlantaparts.c...rm=25860-50060

The canister assembly is here:
https://www.lexussouthatlantaparts.c...774050030.html

Keep us posted, can't recall that issue coming up so I'm interested in what you discover.

 

I ended up cleaning out the throttle body/MAF and in doing so noticed that the EGR ports inside the intake were almost completely clogged. Ran a couple cans of seafoam spray through the egr ports and the throttle body, cleaned the EGR valve out again and so far no more codes. Engine seems to be breathing more effectively. The EGR is electronically operated in the 95-97, and there is no VSV that controls it's operation.