So when I first start the car, put it in gear, and step on the gas (normally) the gas pedal pulsates slightly pushing my foot up then back down. I have done searches on this forum to no avail, lots of brake pedal pulsates but not with the gas pedal. I did know about this when I got the car but the PO just said it goes away while driving lol.

When I first went to view the car prior to purchasing it, the test drive was weird because I would step on the gas, again normally, but it wasn't moving, nor did the engine's RPM climb, I was only moving on the normal off-brake momentum. It took a couple of presses on the gas for it to "kick in". I haven't experienced that part since I bought the car a few weeks ago but I do continue to experience that slight lift & release of my foot from the gas pedal every time I start the car and go. It only does it the first time I start the car then it's fine throughout the driving range regardless of how long I drive for. Transmission shifts smoothly.

Any ideas?

 

Unplug the connector at the traction control unit and see if anything changes. The ABS and Trac Cont lights will come on....that's OK for now

Cheers
DD

 

I got into the habit of just turning off the traction control until I get it fixed.

 

Thanks, guys, I'll give it a shot.

Funny, I've read a lot of different posts in the past for un-related
issues where it was suggested to disable the traction control, and
monitor it. Funny because I wondered if I'd ever have to do that
on my XJR as a test for anything lol.

 

I turned off the traction control at the switch but there was no change.

Today was actually the frst time I purposely spun the rear tire. I had to because I was on that type of pavement I knew would make a screech lol but when I did, it squeeled as expected but then it just kind of cut out, it didn't stall or sputter, it just didn't continue to spin or rev engine so I let off the pedal and drove as per normal. It was exactly like how I stated in the beginning of this thread where I push the gas and get no response until a minute or two later. It's not a transmission issue because again, the engine doesn't make the rev sound. Very odd to me.

 

Unplug the connector at the traction control unit and see if anything changes. The ABS and Trac Cont lights will come on....that's OK for now

Cheers
DD

 

Its a long shot, but does your car have cruise control? Could it be playing games with the throttle? If it is fitted, try undoing the little metal connecting strap between the bellows and the throttle, thus disabling any influence it might be having. Worth a look see as it only takes a minute?

 

Clean the throttle plate/bore and go on with your life.
Here is some info from years ago.

I don't think the breather kit is still available but I installed DOZENS 'back in the day'.

bob gauff

 

I'm not positive, but I think you have two different things going on here. One is the business of pushing the pedal down and the engine doesn't rev up. That's probably a sticking throttle plate [butterfly]. After a couple of presses it will break free and you can drive away normally.

The other business, the sensation of the pedal pushing back at you is most likely the traction control activating. You said you can turn the traction control off and nothing changes. That sounds like an unintended actuation of the tracs control. I'm curious, watch the column of warning lights at the LH side of your instruments when you turn the ignition on. They should sequentially light up from bottom to top, then go back off. I want to know whether the TRACS and ANTI-LOCK warning lights are working. I'm wondering if the system registers a fault when it pushes back at you, but can't signal you with the lamps.

Something else to do is to find a gravel lot somewhere and test your anti-lock brakes. In gravel your ABS should activate nicely, if the brakes just lock up, we're onto something.

Wouldn't be the first time someone has sold a car with warning lamps defeated.

Good luck!

 

Apparently I wasn't doing that simple task properly. I only pressed & released it, not press down and hold for a second like I should have.

If I had listened to xjrguy when he asked what lights appear on the dash, I would have said none which would have indicated something not right with TC because if I had turned it off properly it would have shown in the dash like it does now.

The problem with my pulsating pedal appears to have gone away with [properly] turning off the traction control at the dash. If that wouldn't have worked I was going to unplug it under the hood as Doug suggested; not once, but twice because I didn't listen the first time

I owe it to all that have replied, and others that have found this thread by searches, to come back and let you know your suspicions were correct, but more importantly, to thank you.

 

I'm guessing my TC unit will need sent to Module Masters one of these days.