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[Strangechap]

2 weeks ago I changed my camcover gaskets, cleaned the breathers and put in a new thermostat.

(You lot aren't mucking about when you called it the b-bolt were you!)

After managing to turn the pile of parts on my garage floor back into something resembling a V6, I'm happy to report it works still, and I had no bits left over.

Except I've noticed at speed, say 50mph plus, and when the car is hot, when I press the throttle to either accelerate, or maintain speed up a hill, the throttle pedal goes all 'bouncy' and stiffens, like I'm trying to push it past an obstacle. It almost kicks back against my foot. It's odd.

When that happens, the gearbox kicks down a gear.

And it shouldn't do that, before it would just accelerate and only kick down with a spirited press of the pedal.

What have I done? Or not done.

I've checked the vacuum pipes.

The throttle cable is not loose. It has cracking to the plastic 'skin' on the cable and I was worried this was catching on the cable outer at a certain point, so I put some tape over it to assist it into the outer. This didn't fix it.

Obviously I had the throttle and linkage off to do the work, so I must have disturbed something, but for the life of me I can't see what.

The car is a FL V6 3.0 estate with an AR35 box. I replaced the box last October so it has new fluid and filter.

Just seems a coincidence that I've noticed it after doing the work. Must be linked somehow.

Any suggestions greatly appreciated.

Tim

[cam.in.head]

it sounds like the throttle cable is maxxing out some where along its travel causing the kickdown switch to operate. does the weird feeling pedal happen all the time .engine running or not.

[Strangechap]

No, this is what I don't get - engine off, pedal feels normal. Driving at normal speed, pedal feels normal.

Driving fast, pedal usually feels normal, until it starts misbehaving.

It's like it only does it when the throttle is further open, like when I'm going fast.

How is the kickdown switch activated? Is it a button that is hit when you floor it at the end of the pedal travel, or does it work by pressure and doesn't have to be floored?

[Strangechap]

I'm wondering if disconnecting the kickdown switch and driving it would help rule out the kickdown causing this:

http://workshop-manuals.com/vauxhall/omega-b/k__clutch_and_transmission/automatic_transmission_rear_wheel_drive/automatic_transmission_ar_25/35/repair_instructions/kickdown_switch_remove_and_install_%28vehicles_with_4-cylinder_petrol/v6_engine%29/

[zirk]

Theres a circlip that stops the throttle cable wandering (at the Throttle Body end) did you fit this back on?

[cam.in.head]

yeah check circlip is in place .this takes up the slack depending on the groove it is in. make sure mounting bracket has its two bolts in tight and generally look for any signs of catching or movement whilst someone operates the pedal for you (engine off).check pedal end too. strange how it only does it whilst driving.also worth an easy enough to check if spindles / butterlflies are not loose due to loose or missing screw or just badly gummed up.also if you have cruise control make sure this isnt causing this at the engine end

[Strangechap]

Yup, all is tight and the clip is there. I re-tensioned the throttle cable yesterday to check it was correct.

The car was acting up again tonight, it happens in exactly the same stretch of road each time!

I discovered today that the cruise control is working intermittently too, whereas it was fine a couple of weeks ago (I use it on a certain 30mph stretch to ensure I don't speed there) and today it wouldn't work.

I suspect the issues are linked. I'm wondering if the feedback I'm getting through the pedal is the cruise control servo kicking back.