When accelerating, the car will reach 2500 rpms, at 40 mph. When driving correctly, the car is at 2000 rpms while at 40 mph. It putz and acts as if it's going to die. While I'm at a stoplight, the headlights brighten and dim as the
car struggles to run. I recently replaced the plugs, wires, air filter, cap and rotor. Basically a whole tune up, but the problem still exists. It doesn't always do it, and with the rpms up, I don't feel iys a gas pump issue. Any ideas would be greatly appreciated!

Thanks in advance,

 

Texas gal:


The dimming of lights is a big clue. Low volts for ignition. Time to check connectors and wires and grounds.


Could it be that the RPM differences indicate the trans has not yet shifted from 2 to 3!


My guide for almost all critters s to get the electrics right before attacking fuel issues.


Usually works, and no need to get into fueling.


Carl

 

it could be the Coolant Temp Sensor acting up.

the Sensor, not the Sender.

 

The car does shift from 2 to 3 when hesitation is occurring. It seems the hesitation only occurs when the car is first started and has not been driven for a long enough period of time that the engine cools down. The hesitation will last usually 2-3 miles. I let off accelerator for approx 3 seconds, then engage acceleration again. I do this approximately 5 times, and then she starts driving as if nothing ever happened. I don't know that if I DIDN'T engage, let up, engage....if it would still correct it's self. Any other ideas?? I appreciate your help VERY much!! I totalled my truck last fall with liability only, so the Jaguar has been my daily driver since.

 

southerngal,

the hesitation only at first start signals as well as the erratic electrical behavior suggests that its probably an electrical problem. I completely know what you mean when you describe being able to engage and let up with accurate timing to keep it alive but being unsure if it would work.

I would suggest the following cheap/no-cost solutions in this order:

1. cleaning and replacing any missing/frayed ground connections and battery terminal connections:



2. cleaning the Air Flow Meter and replacing the air filter.
Clean the AFM and the air intake tubes as well as make sure the seals and connections and tight and not cracked along the intake area. I recently upgraded to a K&N filter and I hear and feel a noticeable increase in responsiveness (although I made that and other changes simultaneously).

3. replace coolant temp. sensor.
this is a little blue plug running along the rail with a single wire connector. cheap and very easy to replace (<$15) so its good to just eliminate the chance it could be failing.
Welsh Enterprises, Inc - Jaguar XJ6(88-94) / XJ40 Fuel/Emissions Switches, Sensors & Injectors Parts - Coolant Temperature Sensor - XJ6 XJS

4. test/recharge/replace battery as needed

if these don't correct your problem, I've also had success improving stable idling and reducing hesitation by removal of the entire air pump system and plugging the lines, treating gas a few times to remove small deposits in injectors, as well as changing the fuel filter (and repeating frequently only if you see lots of deposits/mineral/residue in your filter when you remove it).

hope that helps!