Vacuum issues

The vacuum line to the brake booster is a common failure point, so check that. The rough idle when its wet could be an ignition coil pack problem. Have you scanned for any codes?

Thanks for the reply.
I have changed vac pipe to the brake booster and no joy there. I think the problem with the brakes and idle are one and the same. Both issues started at exactly the same time after running through the puddle, they also corrected themselves at exactly the same time and the car drove perfectly for 6 months until running through another large puddle when both issues reappeared. Every now and then they will clear and the car will run fine. I think that it might be an electrical issue that’s why I was asking if the car has a vacuum booster pump (electric not mechanical) hoping that this might be the issue.

Do you have a automatic? There is a vacuum pump and plastic pipe; that goes all the way down to the automatic transmission and the pipes split, the vacuum pumps can fail, causing brake issues.

Here is the service manual for a 2006 with ah 2.5L but I would assume, it probably is similar to yours?

Here is a thread; where a member, had a bad pump, this might be a good thread to review.

Smileybug said:

The vacuum line to the brake booster is a common failure point, so check that. The rough idle when its wet could be an ignition coil pack problem. Have you scanned for any codes?
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billymade said:

Do you have a automatic? There is a vacuum pump and plastic pipe; that goes all the way down to the automatic transmission and the pipes split, the vacuum pumps can fail, causing brake issues.

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Thanks billymade. No it’s a 5 speed manual.

You might try replicating the issue with a small hand pump squirt bottle filled with water. Jack the front of the car up remove the front tires. Start the car, start spraying the underside of the car, when the idle changes you know you’ll have found the vacuum leak or bad electrical connection.

Brownie69 said:

Thanks billymade. No it’s a 5 speed manual.

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Does the EGR valve use vacuum? This is now showing a fault so will look into this.

Good question, we never got the 1.6L here in the USA and from what i can tell, the engine has gone though a number of changes over the years. Do you have a service manual for your car?


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billymade said:

Good question, we never got the 1.6L here in the USA and from what i can tell, the engine has gone though a number of changes over the years. Do you have a service manual for your car?


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Problem solved. The EGR valve was permanently open, allowing to much gas back into the air intake (rough idle) and killing the vacuum (hard brake pedal at low revs) I plated it off today and the problem has gone.

Do you have any photos, parts or install info; to share, so the next 1.6L owner with the same problems, can benefit from your experience? Is there any reason; why you did not just replace the defective EGR valve, to resolve the issue and will there be any future problems with it being blocked off? Thanks.