I have a 1999 Vanden Plas with 67K that hesitates and misses on acceleration from stop and sometimes accelerating cruising a 50 to 60 mph. The check engine light comes on. I changed the fuel filter. Any ideas?

 

Get the codes that are causing the check engine light to come on. You can get an OBDII scanner/reader for under $100. Without the trouble codes it's a crapshoot.

 

Confirming what JimmyL stated, you need to get the code and work from there. There are 100+ things that can cause your issues, from a clogged air filter to a bad cylinder on the engine.

 

Will do. Local dealer will not service a Jag that has been serviced by a shop other than a Jag dealer. I have been told that only Jag dealers can read all the codes - incorrect? If I use a scanner, where do I find what the various codes mean?

 

There are generic OBDII codes and there are manufacturer specific codes. You can get a reader that will read manufacturer specific codes but it's not worth the money for me, at least not yet. If you get the codes you can post them here (generic ones) and/or you can download a PDF with all of them on it. It's not going to tell you the exact problem, but will definitely point you in the right direction. You can use it on any car after 1996, so it's a good investment for a reader/scanner. The codes may even be posted somewhere on here.

 

Go to AutoZone, they read the code for you for FREE!

 

Thank you, JimmyL. Free at AutoZone - now there's a deal! Thanks SBreeen!

Great Forum.

 

I'd steer clear off your local dealer, if that's their attitude! Try to find a local Jag specialist, or even better, follow the advice here and fix it yourself.

 

I read the codes for the Jag and they were PO171 and PO174. Both were fuel related codes. There was a PO1111, but as I understand it that this code means that the code reading is complete.

 

P0171 & P0174 are engine lean codes, either an air leak between the MAF and throttle body, probably the seal on the TB or a split in the induction tube....or.....did you change the filter and the symptoms appeared, or was it an attempt to cure the symptoms?

I ask as another item listed under these codes says blocked fuel filter - which has a fluid direction arrow on it...

Engine misfire
Air intake leak between MAFS and throttle
Fuel filter, system blockage
Fuel injector blockage
Fuel pressure regulator failure
(low fuel pressure)
Low fuel pump output
HO2S harness wiring condition fault
Exhaust leak (before catalyst)
ECM receiving incorrect signal from one
or more of the following components:
ECTS, MAFS, IATS, TPS

Hope this helps you cure the issue

 

I had those codes when I first got my, found the tube on top of the throttle body was slightly off the gasket. Haven't had the codes come back.

 

Thanks Sean B. I replaced the fuel filter (arrow going in the right direction), removed the air filter and components from the throttle body, cleaned the throttle body and carefully reinstalled the air filter assembly, making sure there were no leaks.

I am going to try an injector cleaner and see if that helps.

This has gone on so long that I would think that if it was the fuel pump that it would have failed by now. I am resisting the temptation to replace it.

Only happening with high demand on acceleration seems like a fuel pressure problem.

I appreciate all the feedback and support from you and the rest of the forum.

 

Before I even considered changing the fuel pump, I would check the fuel pressure. A fuel pressure test guage costs lest than $50, but you have to either get one with a few feet of inlet tubing ro rig that yourself so you can tape the guage to the outside of the windshield and run the car at speed.
In my case, the inlet sock to the fuel pump was clogged.
The fact that the drivability is only affected on high demand might be a symptom of the fuel system "winding up" at lower demand. If you have not done so already, CAREFULLY check the full load breather tube, the one from the right cam cover to the induction tube for lengthwise cracks along the bottom.