Carpokes Porsche Forum

After finishing clutch install and completing reassembly, I am experiencing intermittent stalling/hesitation on acceleration.
Wondering if I might have switched the vacuum hoses on the wastegate (Lindsey dual port). Would this have any effect?
Have switched hoses and and garage start sounds better. Have not had back out on street under load. Will recheck grounds as well. Seems like a vacuum issue.

Figured it out. Top port goes to banjo bolt per Lindsey website. Sooo, moving on, may not have set the gap correctly on the reference sensors???

Sorry I missed this till now. Stumbling on heavy throttle, but driving fine otherwise, is often the first sign of a weak ignition. Spark plug wires are an often-overlooked culprit if yours are old, along with good cap, rotor and plugs (gapped to spec or less). The speed and ref sensor gap is not a likely cause of stumbling/hesitation under boost. Their signals only get stronger with RPMs, and generally they either work or don't work.

Worth re-checking all your couplers too if you have reason to think it's a boost leak. Do you have a wideband?

Thanks for your response. Yes, I do have a wideband.

zoom944t wrote: Thu Jun 29, 2023 1:44 pm Thanks for your response. Yes, I do have a wideband.

What happens to the AFR when it starts to sputter? Do you see it going lean or rich before it starts acting up?

My recollection was that it was going lean. I will pay specific attention next time out. What would a lean condition represent?

Depends on if you are in vacuum or boost. If it goes lean while boosting, that can cause knock/pinging and compromise the head gasket. If it runs lean under vacuum, and then rich on boost, that's more likely a vacuum/boost leak. Maybe take a video of it hesitating/sputtering so we can get a better idea what you are dealing with.

How old are you plugs, wires, cap and rotor?

Solution (fingers crossed). Corrected the gap on the reference sensor and problem has resolved. Now runs normally without faltering. Boosts correctly. I have read on multiple sites that reference sensor is only operable on startup. My experience would indicate otherwise. Thanks for all the suggestions.