Well I installed the fuel pressure sender and hooked it up to the ecu. Seems accurate, the regulator is vacuum referenced so my idle pressure is right around 40psi. If I pull the hose off the regulator it goes up to 44-45psi.
I had the opportunity to get it out on the highway for a solid 1 hour of highway time and data logged two 30 min sessions. Its at least 15 to 20 degrees(70F) warmer out than it was when the stumbles were occuring during last weeks criuse(52F). I let it idle in my driveway for 10 to 15 min hood closed to get it really warmed up before we hit the highway. Were cruising at 2200 rpm and at around 22 minutes into the first cruise we feel a very slight stumble and thats it the second 30min never felt a thing. So I look at the data around that time and I dont see anything major. The average fuel pressure is between 36 and 40 psi the actual A/F is around 14.5. I noticed the fuel pressure tracks the KPA graph very closely, I imagine this due to the vacuum reference. When I roll out of the throttle and rpm comes down getting off the highway the kpa goes down significantly(18kpa- 36psi) as does the fuel pressure. I really thought the stumbles would happen more frequently since it was warmer out but it didnt. Does the colder air make it much leaner? What do you guys think?
Thanks Rich
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