has anybody came across a rough idle when sitting at lights or stop position with the foot on the brake while in gear? i put the vehicle bak into nuetral and the idle returns to perfect still with my foot on the brake.

i believe i have traced it back to a vacuum leak in the booster but am not certain, the vacuum lines are fine so could this be an internal fault?

input appreciated

if you can hear a hissing under the dash its the booster its most likely the engine mounts

Block off the vacuum line to the booster, your brakes will still work but they'll be bloody heavy so careful. if the problem goes away check the vacuum line carefully, if you can afford it, change it on spec. if its OK then you probably have a hole in the brake booster diaphram and you gotta replace it. Bugger.

How did you track it down to the booster? :D

how did you track it down to the booster? :D

i brought all the induction specs bak to MS, like the throttle stop screw and the base idle and the plugs and leads changed not too long ago, and since it was only wen i applied the brake when i stop, still in gear i pull the hand brake and release the foot brake and the vibrations stop, re apply it and its bak, also the revs fluctuate a bit, but knowing the booster is vacuum assisted i assumed it was a vacuum leak - no hissing sound though???

being the cheaper option i mite try the engine mounts firstly and kik myself wen it turns out to be the booster

to test bosster hold foot on brake while motor running then turn engine off if ya foot rises its stufed if it stays its ok

to test bosster hold foot on brake while motor running then turn engine off if ya foot rises its stufed if it stays its ok

Or conversly you pump the brake a few times with the engine off, then with your foot on the brake start the engine. If the booster is OK the brake peddle should sink down a few Cm's. :)

It's not always one problem for the cars, use the search thread there is alot of different fixes (yes its a pain in the ass problem).

My Steering wheel was shaking(vibrating) at the lights, since changing the TPS switch has smoothed it out, now I have none. Also I only use premium petrol which I find helps aswell.

good luck with it.

My Steering wheel was shaking(vibrating) at the lights, since changing the TPS switch has smoothed it out

i suspected my TPS for an unrelated problem not too long ago, went to the mitsubishi dealership and it turns out they are obsolete, for a TR magna anyway

all TR's i been in do this at the lights. common prob.

I have also seen auto 4cyl magnas that Idle rough when stopped in gear and run fine otherwise, in one case the rough idle went away when the tired transmission was replaced.

A TR auto will also idle rougher and engage gear hard when the transmission computer fails or loses power (in this state it will only have 3rd gear in D).

A magna brake booster will also lose vacuum quickly when the engine is switched off if, the plastic one-way valve in the booster vaccum port is missing. This won't affect idle.
(the valve can get caught in the hose and disappear if the hose has been replaced)