Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
volumetric efficiency is 85%. smoke tested intake when cold to eliminate an intake gasket that seals when warm. pinched purge valve line off. front air fuel ratio sensor reads 3.3 volts at idle rear o2 reads normal range. both react to rich/lean conditions. fuel pressure was taken and read 50 psi. during loads it didn't drop off either. it goes lean under load. what is a good flow for an injector balance test?? I plan on going after the injectors and was wondering how much of a drop should I see. previous guy replaced rear o2 sensor did not fix it. other guy replaced maf. the dtc set at 58 mph
Typically I would say that doing an injector balance test will show results of exactly the same drop across the board if they are goo. If you see a difference in any of them, you have a problem. I know this will sound strange, but I have seen these cars do this if someone installed an aftermarket lamba sensor and on one occasion I had one with an aftermarket air filter cause the problem. If you say this happened at near 60mph it is probably not a vacuum leak as the car is warm and at cruise.
"The man who says it cannot be done should not interrupt the man doing it."
I'm with Joe about the injector drop. If they're all even, then I figure they're OK.
Any chance of ethanol fuel in the tank? Dunno if you have an injector flush machine or not, but you can use it eliminate a fuel quality issue. That'd certainly account for a stubborn lean condition that gets worse under load...
Check the PCV hose and valve, also break booster for vac leaks,
If that is good I would test the engine temp sensor. If all good I would do a volume test and psi . If that is all good then drop test all injectors and see if the is a big difference in reading. Also note if they are all the same brand, I have found that if someone change one with an after market instead of oem one it may be a problem.
This should be a good starting point.
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