98 XJR - it's been running great, except for an intermittent long crank/no start, which i won't get into.

I started the car and drove a bit (everything was fine)- all of a sudden when I gave it gas it would not accelerate - it would barely surge, and pretty much starting losing speed. I drove into a parking lot, and could not get it to accelerate above 5-10mph. The idle was low and rough, like it wanted to die. Throughout this all, the restricted perf. and check engine lights did not come on at all. Then i shut it off, restarted it, and it drove 100% normal the whole drive home. I have no idea what the hell just happened, but it makes me nervous to drive the car now. You would think if the car will not accelerate and almost died that the restricted performance light would come on, but nothing did.

Anyone know what this could be? Wasn't there a recall on the throttle body, stalling issues, etc.? Could this be it?
thanks in advance.

 

......and the throttle body is currently clean

 

Throttle position sensor fault behaves like that, although the idle was not affected when I have driven a car with this symptom. That means a new throttle body.

 

Sunds like a throttle body yes

But it would be wise too look for diagnostic codes first.

 

Does anyone know much about the throttle body recalls on these cars? I believe jaguar replaced the throttle bodies for free under a recall (my previous owner must have missed the bulletin) but what I don't know is what is different about the replacement. I suspect that the intake plumbing, etc., is different, which probably means a new EGR valve, new elbow from EGR to exhaust, etc. Also wondering if an ECU reprogram is necessary. There was something in the throttle body recall bulletin that mentioned some cars needing an ECU reprogram, depending on vin#.

 

hah damn dude, youve had the most problems yet on your ride, yet you love it dont you! :P Yeah im debating to ditch my old 98 soon, not worth the upkeep anymore to be honest... my 04 has been problem free foralmost 6 months now.

To answer your question, Yup. Check out my post from before when I had the same problem What a good ole simple search will do!

https://www.jaguarforums.com/m_53864..._/tm.htm#53864

Its throttle body related. If you read my post you will see that there was a recall. My was replaced in May 2005 but eh still did the stalling problem, andthe compwas updated as well (ECU reprogram was done same time by dealership)

Merely ask one of the dealertechs here to run your vin and you will know asap if it was done as usual. Goodluck dude, hope that thing comes around for you!

** I got my whole throttle body cleaned like 3 months ago. It was completely filthy. Comp had been soft-rest but since the clean my shifting has still be a lil odd coming down from 3rd to 2nd into 1st only. My car also seems to upshift a gear at like 50-60 coasting after that as well, bring down the rpms and constantly engine breaking, eating a lot more gas than usual. It seems to be a hit or miss when you start it up, cause it doesn't do it all the time. Sounds like ECU having problems adjusting to me. I can reset the battery and it works fine for a few days, smooth shifting,then it slowly goes back to the hard late shifting coming down in those gears. Sport-Comfort mode matters not, same deal. Funny cause I've only had the 98 car for 1 year Feb 9th and invested over $3000k in it.

 

Greetings Scott,

The throttle body replacement/ reflash service action was a recall: as the current owner, you can ask your dealer or Jaguar if there are any outstanding recalls for your car. If the throttle body on your car now is the one that came on the replacement engine, it may or may not have been renewed. Point is, even if your car is in the range of units requiring replacement, I would think a "one per customer" rule negates all other questions.

The replacement throttle bodies have a sticker affixed to the top, it is a pictogram of an eye looking at a repair manual. That serves as a noteto consult the information which warns of using harsh cleaners in the throttle bodyand damagingthe molycoating inside the bore. If the thottle body has a sticker on it, then the original unit that is now on the engine in your car has been replaced with an updated TB. Unlikely you'll get a freebie.

I think you told me that you had to remove the throttle body to replace the camshaft position sensor, and this new symptom has appeared a shot time afterward. I would make certain that the throttle body harness connectors are clean and secure, perhaps the R&R affected a connection. There is a bulletin about this too, although not a recall: it involves replacing terminal pins for TB connectors because of a mismatch in materials.

Since you did not have a Check Engine Light illuminated, I don't believe your scanner will show a P code as a result of the event. WDS or IDS may show a CAN circuit fault code, and that will point to a throttle position sensor interruption if that was indeed the cause. Cars I have seen with the fault you described had both P and C codes which identified the TPS, and a throttle body replacement fixed the cars.

Andrew Bernstein
British Auto Care

 

thanks guys. atom.. yes I still love the car... but my wife would love nothing more than to drive it off a cliff!

It's been driving fine since the "weird issue", but I don't plan to ignore this and wait for it to stall on me on the highway at an unexpected time. JTO - I'll make sure I buttoned everything up correctly on the throttle body, as well as clean the connections as you suggested.

My throttle body did not come with my "new" used engine; it's from my original, dead engine. I suspect it was never replaced, and I think so for 2 reasons: 1) there's no sticker to be found, as JTO described. 2) several months ago I replaced my EGR valve. I ordered one from a parts supplier - they all had the wrong one listed, as it did not fit my intake plumbing. I then ordered one from jaguar - and received the same wrong one. I believe the assumption was that most-to-all TBs had been "upgraded", and the EGR they were selling for a 98XJR fitted the intake plumbing on the upgraded TB, but not the original. That's the only way that I can explain a jaguar dealer sending me the wrong valve. What I ended up doing was getting one from Ken (he pulled one off a salvaged 98 that was sitting around).

either of you know if the EGR and EGR elbow pipe have to be replaced with the throttle body replacements?? If so, this could get expensive. EGR valves for jags are not cheap, so I've learned.

 

not hey dont get replaced with the throttle body.. if you need a TB or a EGR let me know..

 

I'm curious about this. You mean that if I post my VIN, someone here will run it and let me know if the recalls have been addressed?

That would be helpful. I just picked up a 1999 XJR yesterday. Love it, and hate it! hehehe... Been working on it two days straight getting kinks out. No heat, No lights, cosmetic issues, etc...

Everything is now working, except still don't have working Auto Headlights, but assuming that is because my rearview mirror is cracked. Aren't they somehow connected because of the sensor in the mirror?

Love this site! Thanks everyone for all your insight.

 

sure gimme the vin or email it to me jag_genius@hotmail.com

 

I can't think of a reason it's dangerous to post it here, so here goes.

SAJPD1842Xxxxxxxx

Thank you very much for your help! I had no idea a site like this even existed until I bought my car. I'm into electronics, and often use forums for that, as they're a great resource.

I hope to be able to help here when possible.

Sorry, should have emailed, got off topic... sseslar@gmail.com