Fox T-Bird/Cougar Forums

Technical => Engine Tech => Topic started by: Axlehead on August 30, 2007, 05:00:13 PM

Title: Thunderbird Running Lean
Post by: Axlehead on August 30, 2007, 05:00:13 PM
Ok well the issues are continuing for the 87 that I added to my collection a month ago. The car throws code 91. I recently did a tune up, replaced plugs, wires, coil, and cap and rotor. Before the tune up it threw 41 and 91. Would it running lean cause the idle to get messed up at operating temperature? The weird thing is that the car runs fine until it gets to operating temperature. But once its warm it stalls and idles irraticaly. I was told to replace fuel filter and coolant temperature sensor. Any ideas guys?
Title: Thunderbird Running Lean
Post by: Axlehead on September 06, 2007, 04:03:40 AM
What could cause this? Its low mileage so I hope it isn't anything big. EGR Valve perhaps?
Title: Thunderbird Running Lean
Post by: 32VFoxBird on September 06, 2007, 10:15:46 AM
vacuum leak or O2 sensor/bad ground.
Title: Thunderbird Running Lean
Post by: Axlehead on September 06, 2007, 03:16:54 PM
02 Sensors were replaced about two weeks ago. Was one of the first things I did when I encountered the problem.
Title: Thunderbird Running Lean
Post by: quicksilver on September 06, 2007, 10:28:14 PM
maybe one of your vacuum hoses isnt clamped down, so when it get hot, the rubber expands which would cause a leak.