'92 XJ40, 150k miles,new head gasket last year, tune up, etc.. Running fine in town, stop and go up to 45 mph, no problems. When entering freeway, runs fine while accelerating to 75. Stutters and acts like it's missing or has tranny problems when trying to cruise at 52-55 mph. VCM says fuel fail 37.
EGR would not hold vacuum so replaced it. Can the EGR temp sensor be the problem, or more likely the solenoid?Or am I looking at some other culprit?
Looking for ideas. Found a used sensor nearby; any test to verify if it is good?

 

Have you checked/replaced your fuel filter? Is your fuel pump good?

 

The EGR will not hold a vacuum by itself.
It needs to have exhaust back pressure to operate properly.
Fuel fail 37 is for the vacuum solenoid, not the valve itself.

Have you downloaded the AJ6 Engine Management .pdf I uploaded years ago?????

Look in the large file section.

bob gauff

 

Also not mentioned here is that you might not be getting fuel to all cylinders(most likely a plugged up fuel rail) I had a similar problem which would happen when the tranny torque converter would lock up,then there was a shudder which felt like drive train related,and after about a month of workin on it found the fuel rail problem.

 

Swapped vacuum solenoid from front of engine (Air injection or cruise control??) with EGR solenoid. That cleared code 37. Still have rough running at constant highway speeds. Runs fine under acceleration, and at speeds less than 50 MPH. Tried to reset idle using info from this forum (had to do twice). Idle now correct, but fuel consumption went way down according to VCM and now have code #12, Airflow sensor problem. Can this be related to swapping solenoids or resetting Idle? Will order new vac. solenoid for Egr system and swap back temporary replacement.
Will pull off fuel rail and check for blockage/ corrosion and try and eliminate that possibility. Thanks to all that offered suggestions.

 

Keep at it shelby and please keep us updated