Earlier this afternoon I took the Jag out to run some errands. It was pretty warm out and I had the A/C going. Transmission in non-sport mode. I'm driving along like normal and the throttle starts to flutter a bit and surge. Then apparently it decided that I wasn't going fast enough and tried to drive into the car in front of me. I held my foot on the brake pretty hard as I came to a stop for a stop light and the throttle is just opening and closing repeatedly. Once I can, I pull it into a parking lot and turn it off and on again, which seems to fix it a little bit, but even as I'm heading straight home it starts to flutter a little again.

I just finished taking the throttle body off and checking for any corroded plugs, vacuum leaks, blocked ports etc. and didn't really find anything bad.

I'm assuming that the Throttle body is on its way out, though its not throwing any codes besides the traction control failure.

Has anyone tried to rebuild these themselves? Any source for the electronics/ sensors attached to it? Or should I just get a used one and hope it's not bad.

 

Not sure this will help but you may want to read this, it refers to a service action on the throttle body. https://www.jaguarforums.com/forum/s...ghlight=brakes

 

I wish that I would have caught that, it looks like it expired at the end of 09.

 

That is correct it did expire! You may want to call or go by the Jaguar shop and see what they will do for you. If they like you and they can they will. If this is not an option then you can see if a reconditioned one is available. I have this link on my page and would like to know how you make out if you elect to use them. http://www.jaytanindustriesinc.com/ Good Luck!

PS we did all we could to post this information for everyone to see. A real shame it was not available to you.

 

I had the exact issue, but usually at near idle - wanted to accelerate all by itself. It occurred, perhaps, 20 times over several months without throwing a CEL and code, until the last time which led me to the cause.

The TPS (Throttle Position Sensor) connector had corrosion on the pins, and cleaning with contact cleaner/lubricant, as from Radio Shack, eliminated the problem.

Jag has a TSB on this also, they used tin pins in the harness connector with gold pins in the TPS body - galvanic corrosion occurs which causes the ECM to get misinformaton about where the throttle motor/butterfly is, causing the throttle surging.

The cleaning is easy, and quick. Replacing the tin pins with gold is the final solution, but the cleaning has worked for 3-4 months for me with no issues yet.

 

This might help http://www.gusglikas.com/AutoRepTB.htm my car did not have the acceleration problem.

 

I will try cleaning the pins with some contact cleaner and some q tips along with some other sealing/tightening of the intake / electrical system.

I'll report back if that works. The problem has been pretty consistent in the warmer weather here recently.

 

you can get new gold plated pins from jaguar if your are bad??

let me know if you need some i can get some for you

 

A similar thing happened to my Dad when he was driving my XJ8, turned out it was a simple thing. It was the was he held the steering wheel sometimes, his hand was just catching the cruise control button, and causing the car to surge a little. I know this may not be the issue in your case, but just thought I'd share this in case this is what others may be doing when checking this post out in the future.

 

Ok, here is some follow up. I took the throttle body off and sprayed the bajeezaz out of all of the connectors/pins etc. with contact cleaner then gently rubbed them with some qtips/contact cleaner to get any corrosion off.

While that was off I noticed that one of the hard plastic vacuum hoses going into the passenger rear side of the intake manifold, right under the throttle body was not a very tight fit. Its got a plastic guide that holds it in and a couple of the tabs were broken off of that guide. So I RTV'd that into place in case that was the source of a vacuum leak.

Once I got it all back together I sprayed out the harnesses going into the throttle body sensors and the MAF and put some dielectric grease on them. I couldn't see any corrosion anywhere on any of the plugs or pins to be honest but there was dirt coming off of the q tips.

Then I did a hard reset to make sure I was starting clean.

Annnd, the surge is gone! I can use the A/C in the insane heat here (The surge was worst when it was really hot out.) and it runs fine. It seems to Idle a bit better and adjust more quickly to varying conditions.

I do still get a squeaking noise that is matched with the throttle, (not vehicle speed or engine speed) which I assume is the throttle body motor, but it drives the best it has since I bought it.

Thank you all so much for the input! This has really saved me a great deal of money. If it comes back I will look into the dissimilar pin issue and replace them.

 

On the road again! That works for me!!

 

GREAT! Glad you had success.