Any Ideas, I battled and won code 332 (which throws a CEL) about 2 months ago. Now I decided to pull codes and got the 334 code, and its driving me crazy. I have replaced EVR, EVP, and a fairly new EGR. !!!

Thanks in Advance

hey check the vacuum i think that code has something to do with the the smog pump or that maybe 331 but i woud check the vacuum lines

Dumb question, but you did reset your codes, right?

Code 334 DPFE or EVP circuit above the closed limit of 0.67 volts.


I am just guessing that it would range from 0.67 volts closed to 5.0 volts fully open. I may be completely wrong.
IF that's the case, could a bad ground cause a higher than normal voltage? Teh problem is, I can't tell which is the ground for it.

In addition, did you check to make sure that the vacuum line comeing from the throttle body is not clogged?

Your coolent level is topped off, right?

Joe, what vacuum line off the throttle body are you talking about? My coolant resevoir was empty the other day and I topped it off. did not pop radiator cap (was hot) The problem with the truck is that if I drive it around town for awhile, and park it, come out and restart it 15 minuites later, it runs rough, real rough, I give it a little gas and head out the parking lot, and its running smooth as can be???