Quote:
Originally Posted by scottfab
You really should rule out a primary fuel pump starting to fail. That is how mine behaved until if finally just quit. No fun getting a flat bed ride home for my baby.
The test is most disruptive but needs to be because the pressure is fine most of the time. You need to get a pressure gauge taped to the windshield mounted on a long extension such that you can see it as you drive. Note what the pressure may be doing on the stumble. Mine would sometimes set a lean code but not always.
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Scott,
I'm in agreement with you. That was my first thought when he said it only happens when car is up to temp. The secondary pump is commanded on full time by the ECM until 176 deg (or 177, I can't remember the exact number). Once that temp is reached, the ECM turns off the secondary pump and only energizes it when secondary port throttles are commanded open. The secondary pump running full time while the car is warming up would mask any primary pump problems below that temp.
Jep