Misfires and lacks acceleration

Tiny
ROMBO12323
  • MEMBER
  • 1996 JAGUAR XJ6
  • 3.2L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 88,000 MILES
Car ticks over fine and accelerates well up to 2000 rpm after that it lacks acceleration and misfires.
Sunday, April 15th, 2018 AT 1:48 PM

4 Replies

Tiny
HARRY P
  • MECHANIC
  • 2,292 POSTS
Either you are lacking fuel pressure or the catalytic converter is clogged. The easiest thing to start with is checking the catalytic converter. You will do that by removing one of the oxygen sensors between the engine and catalytic converter, then take it for a ride. It will be really loud, so do not do it while the neighbors are sleeping. If it feels much better, then what is happening is that the catalytic converter is clogged and building too much back pressure, not allowing the engine to breathe. This restriction causes hesitation and general bad running. You need a new catalytic converter.

If there is no difference, then you will need to run fuel pressure tests. You can borrow a gauge from AutoZone. Here is a general how to guide: https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

You should get 44psi with the key switched on, engine off.

So check the cat first and let us know what you find.
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Monday, April 16th, 2018 AT 4:40 AM
Tiny
ROMBO12323
  • MEMBER
  • 1 POST
Hi, I tried as you suggested but made no difference, it eventually turned out to be the crank shaft sensor. All is well. Thanks for your help.
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Sunday, April 29th, 2018 AT 9:53 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,363 POSTS
Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help.

Cheers, Ken
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Sunday, April 29th, 2018 AT 9:54 AM
Tiny
HARRY P
  • MECHANIC
  • 2,292 POSTS
Ah, okay. That is great! Feel free to come back any time.
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Sunday, April 29th, 2018 AT 6:24 PM

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