2001 Jaguar S-Type Sluggish Acceleration

2001 JAGUAR XJS
Avatar
LEESTANFORD
  • MEMBER
  • 1 POST
Over last 5 months gas mileage went from 18.8 to 16.2 mpg. When I step on accelerator, car runs rough as if a sparkplug failure. I have to backoff the gas pedal for engine to "recover". Engine light has been on for 5-6 monthis on and sometimes registers "6" flashes or sometimes "24" flashes. What could be causing the sluggishness...and what do the "6" and "24" codes mean?
Mar 23, 2006 at 7:04 AM
Advertisement
Avatar
2CARPRO JACK
  • ✓Experienced Mechanic
  • 11,533 POSTS
dont know about the flashes, but it sounds like the Mass Airflow Meter
Apr 25, 2006 at 9:54 AM
Avatar
JUPITER
  • MEMBER
  • 1 POST
i have s type 1999 4.0 v8 and seems to have same problem, on a diagnostic machine it indicated it needed airflow meter one was put on but made no difference :(
Jun 26, 2006 at 9:19 AM
Avatar
FSTRANGER302
  • ✓Experienced Mechanic
  • 117 POSTS
it does not sound like a mass air flow meter. it does sound like a weak coil or oil getting into plug wells. this will cause the rubber insulators to break down and on accleration the spark will jump through the boot to the cylinder wall causing a grounded plug
Sep 20, 2006 at 2:12 PM
Avatar
YY
  • MEMBER
  • 10 POSTS
You may have one or more ignition coils that are starting to go bad. Whenever an ignition coil goes bad, your vehicle will not idle smoothly but will pulsate. You will also feel a significant decrease in power and gas mileage. Your vehicle will also sputter when the accelerator is depressed. If you have any of these symptoms then you may be experiencing an ignition coil problem. The reason the coils go bad is that the spark plug seals leak oil into the spark plug wells and prematurely burn out the coils. To check it yourself (very easy to do) you will need to remove the ignition coil cover which is located on top o the valve cover. This is only about 14 X 2.5 inches and there are only six screws to remove. Once you have done that you will see four ignition coils each held in by only one screw. Once you remove the screw, detach the retaining clip (wire) and it will pull out. Once you have done this, take a flashlight and look inside each spark plug well and see it oil has entered. Hope this helps and good luck.
Oct 11, 2006 at 5:10 AM
Avatar
JAGTECH06
  • MEMBER
  • 7 POSTS
I am a Jaguar mechanic and we have a recall on your year model car. There is a breather neck below your intake manifold that tends to eat away and create a vacuum leak. This tends to make the car feel like it has a misfire and runs pretty bad. This also sets up your MIL.
Oct 17, 2006 at 5:12 PM
Avatar
YY
  • MEMBER
  • 10 POSTS
Dear Jagtech06, isn't the recall on the upper breather elbow only for the 3.0 V6 models?
Oct 17, 2006 at 9:16 PM
Avatar
FSTRANGER302
  • ✓Experienced Mechanic
  • 117 POSTS
[quote:342f4ebab8="YY"]Dear Jagtech06, isn't the recall on the upper breather elbow only for the 3.0 V6 models?[/quote:342f4ebab8] i am a jag tech too. the recall is only for the upper intake elbow on the six cylinder not lower and not for the eight cylinder cars
Nov 14, 2006 at 1:57 PM
🔧 Tools & Auto Repair Parts
Find automotive tools, diagnostic equipment, and replacement parts for your next repair.
Shop on Amazon →
Paid affiliate link. As an Amazon Associate, we earn from qualifying purchases.

Suggested Repair

Inspect the ignition coils and spark plug wells for oil. Oil leaking past the plug seals can damage the coil boots so the spark grounds under acceleration, causing roughness, power loss, and lower mileage. Replace any oil-soaked coils or boots and correct the leaking seals. A mass airflow sensor is less likely, and the breather-elbow recall applies to the 3.0 V6, not this 4.0 V8. The 6-flash and 24-flash codes were not identified.

Conversation Summary

A 2001 Jaguar S-Type 4.0 with about 71,000 miles became sluggish, with mileage falling from 18.8 to 16.2 mpg. It runs rough under acceleration until the driver eases off, and the check engine light has flashed 6 or 24 times. One reply suggested a mass airflow meter, but a similar 1999 S-Type owner said replacing it made no difference. Other replies pointed to a weak ignition coil or oil in the plug wells grounding the spark on acceleration and described how to inspect the coils. A claimed breather-neck recall was later corrected as applying only to the 3.0 V6 upper intake elbow, not the 4.0 V8.

Related Repair Questions

Add a reply
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.

Ask a new question

Frequently Asked Problems for This Vehicle