So I replaced the old stock fuel pump with a DeatchWerks DW200 pump. Had some issue with the fuel line leaking in the tank which is now resolved. Now my problem is when in boost the A/F gauge goes dead lean and car sputters. Car runs fine and A/f gauge is bouncing like normal as long as no boost is present. I pinched the return line and the fuel pressure shot up past 100 psi. The only change was installing the new pump. Only code is 15 speed distance sensor circuit but I wouldn't think it would cause this issue.
I have vacuum at the Accufab AFPR, so I assume it is seeing boost pressure too. New fuel filter - car ran fine before pump change. Any ideas on what to check next?
Thanks, Ralph
Background info: +20s injectors. StageII 86 GLHS LM, Accufab AFPR set to 28 PSI vacuum line on / 35 psi vacuum line off