Lurching?

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May 5, 2007 | 10:31 AM

medic235

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Lurching?

How many people who have the lurching or surging problems are running less than 91 octane gas? When I picked mine up at the used car dealership, they had filled up with the cheapest gas they could get. After the first day it ran crappy.(surging while idling in gear, missing at speed and under load, check engine light on,ect.). I took it to auto zone and had them hook it up and get the codes. They where all emission related codes.I called the dealer where I bought the car and asked what gas they put in it. They admitted that it was the cheap stuff. I ran it down to 1/8 th of a tank and filled it with 93 octane and added some fuel treatment and now it runs fine.

May 5, 2007 | 08:03 PM

badmojo

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Joined: Dec 2006

Posts: 782

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RE: Lurching?

I get slight lurching with 91 or 93 octane but better milage with 93.

May 6, 2007 | 10:30 AM

racerx82

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Joined: Jun 2005

Posts: 3,069

Likes: 13

RE: Lurching?

91 octane fuel is not recommended for the Jag. Your engine is pinging, you won't hear it since the knock sensors pick it up and compensate for it and the ECU makes the correct adjustments for idle and timing. The lurching is the end result from the ECu making these changes in milli seconds but it's not controlling the lurching effectively.

Jag recommends 92-93 for optimizing performance and fuel economy, yes, fuel economy. You will get better bang for the buck and go further with the proper fuel recommend for your car and you won't be damaging the engine.