So this is for my mom's 98 Lx automatic. The issue is that it stalls.

When on the highway or driving around town and its less than a 1/3 of a tank of gas the car will intermittently stall. But when the tank is filled up its better. (It also seems to happen when its damp or wet out but I'm not too sure about that correlation)
The car has a 1457 evap code but I'm not sure that is the problem.

The symptom I found when checking out the car is that it will rev to 5000rpm and the fuel injectors will cut out or at least misfire, so the car wont rev past 5k and then when I take my foot off the throttle the Rpms will fall smoothly all the way down to 0, stalling the car without any hesitation.
I assume this indicates that the car is not able to supply an adequate amount of fuel pressure past 5k.

At idle, the rpms are around 750 however the car will appear to run rough with no large fluctuation in idle.

Im thinking fuel pump or filter and will do a fuel pressure test but want to know if anyone has any other ideas

and also how would I be able to tell if its the fuel pump and not the filter?

All recalls on the car have been fixed.

Thanks

 

Check Engine Light On? If yes, get codes and post them.

Clean IACV, throttle plate, and throttle body carefully. Lack of air from clogged IACV could cause unstable idle during rpm collapse as described.

good luck

 

CEL listed above: 1457 evap code

I did a lot of tune up work a while ago cuz the engine needed some maintenance. I did a brief clean on the intake system but I will take a look at it again.