Fuel pressure too high

[Canadianfox]

Would a 47 fuel pressure at idle with vacuum off cause a 41/91 code ? I blocked off the vacuum line and ran a gauge on the rail and she was 47! I dialed it down to 39 then put the vacuum line back on and she fell to 30/31 .

 

[AeroCoupe]

Well 41 & 91 are left and right banks lean so it’s like someone bumped the fuel pressure trying to correct that.

H

Thread 'Code 41 and 91'

Sep 9, 2008

both for KOER test. 41/91

just replaced the O2 sensors. dont know what could be the problem.

• Haus
• Replies: 110
• Forum: Fox 5.0 Mustang Tech

 

[Noobz347]

Closing this thread: Post this issue in the thread that you created here:

C

Electrical Thread 'New fox body owner little worried'

Aug 19, 2019

I hate being a first time poster with a tech issue but I’ve totally run out of ideas and need some help.Ive done a ton of reading and mechanical work based off the forums on this site trying to solve my issues .

I own a 1993 lx 5.0 convertible and am having idling issues ( sounds like its camed but isn’t) and predetonation ,and à first this last weekend the power lose in 5th,4th where my car just lost speed when I was floored on the highway and all I can watch was my speedo drop .No backfiring ,stalling just power loss until I got to a certain rpm .

Here is what I’ve done based off many...

• Canadianfox
• Replies: 30
• Forum: Fox 5.0 Mustang Tech