Does o2 sensor have to be replaced for a fuel fail 26 code on 1991 jaguar xj40 or is it a vaccuim leak? run great till warm up 27 miles it will only go 2000 rpms at 50 mph running a short time quiti?

SOURCE: 2000 chevy runs rough

fuel pressure regulator might b leaking .. pull vacuum line off of it and see if there is fuel.... if soo replace it

Zak Hanson-Michelson

• 35 Answers
• Posted on Jan 08, 2009

SOURCE: 98 Cavalier 2.4L engine stumbles at 2000-2500 rpm

Could be a short in the wiring for the O2 sensor.   I currently have the same issue only my car finally threw a code after two days of it acting up.  Code 106.  Changed the MAP sensor and it now throws 108, MAP sensor high voltage circuit.  Ah the joys of cold weather and broke down vehicles.  But I know that you wont always get a code with a short.  Let me know if you fixed the problem.

John Quinn

• 286 Answers
• Posted on Feb 10, 2009

SOURCE: 1990 Jaguar XJ40 3.6, where is the fuel filter located?

Hi,
The fuel filter is located under the car, in front and in a little, from the L/H rear wheel.

Undo the 2 nut connections, and fixing clamp, and its off.

Remember no smoking !

Good luck !

A FixYa rating would be nice... Thanks !

John.

SOURCE: Hard start when cold, running rich, poor fuel economy

Chrysler has a bulletin out for a simular condititon that involves replacing the pcm. Heres the bulletin number 18-005-04. This is only 1 possible cause , Fuel pressure, coolant temp sensor, thottle position sensor all can cause like problems. Seeing sensor values and fuel adaptives with a scan tool helps pin point problems.

SOURCE: 1998 chvy 1500 loses power

check the intake gaskets. in the middle front and middle rear. If they are oily, it more than likely sucked part of the gasket in. When it warms up the leak gets bigger. The easy way to check is to get some carb cleaner and spray all around the intake while idling and warm. DO NOT SPRAY ANY EXHAUST PARTS , carb cleaner is combustible. The truck should stumble or even shut off when spraying with the carb cleaner if there is a leak.