i trouble shooting a check engine light on my son's xj8. it has p0171, p0174 and p0443 codes.

i have a feeling there may be a vac leak on the purge vent system. i checked the voltage at valve (part lng1515a) and got 13= volts and resistane across contacts 31ohms.

however the valve noes not chatter like similar valves i have on other cars. Should it cycle or chatter?

in the mean time, i have remove the vac line the draws vac on the cannisters and plugged it to see if it is the source of leak. i cleared the codes and am now driving it around to see if the codes come back. have to drive it alot though. last time i cleared the code after cleaning maf sensor, it didn't recode until after 60 or so miles.

any ideas or thoughts out there.

chris