Car Problems - Help Needed Please

[ribaree]

Hi,
About 18 months ago, my local Mazda dealer replaced my smoking turbo under warranty. All good.
However, last week whilst looking under the car I noticed that the bracket holding the OEM dump pipe was missing and one of the bolts where the bracket attaches to was snapped.
I approached my local Mazda dealer who replaced the turbo about the missing bracket. They said they would install the bracket at no cost since they snapped the bolt and didn't put it back. All good.
The dealer had my car for nearly 2 days because they had to remove the DP and drill out the snapped bolt. They also replaced a split boot on my left side axle.
After I got my car back, I knew straight away something just wasn't right.
The car idles very rough, after it cools down for half an hour or more, it is very difficult to start.
Also my boost guage use to read about 18 in-hg when idling. Now it sits around 14 and if turn on the A/C or turn the steering wheel whilst idling it jumps up to 10.
I took it back to the dealer and told them all this and after having my car for another day came back and said they could not find any problem (suprise, surprise).
Just opening the bonnet and listening to the car idling, you would know something is not right.
Originally I thought it was a vacuum hose, but i have checked everything and found no problems.
I pulled out the plugs and checked them as well.
I must add the car still goes great when I WOT, just doesn't like idling and starting.
I'm now thinking maybe the dealer has damaged an O2 sensor when removing the DP.
Could it be the EGR ??
Any thoughts/ideas would be greatly appreciated
Cheers

[Spudspec]

Might be right with the O2 sensor being damaged dude. Might be worth going to an independant reputable mechanic/tuning shop, and see if they can plug the scanner in, then they can tell you if it is electrical, mechanical or something else.
goodluck.

[Reedy]

O2 sensor won't cause it to idle badly.

[TD]

What month 2007 3MPS do you have?

There was a TSB out in the states about rough idling problems related to the fuel pump, see the attached PDF.

[Spudspec]

O2 sensor won't cause it to idle badly.

Yeah I wondered about that.. the other thing I meant to say was the the airflow meter If you have put a oily airfilter can sometimes react with the airflow meter.. or if it is a map sensor might be damaged or a wire not plugged back in.. or tps could have been upset.

[ribaree]

Thanks for the replies

December 2007 built.
Have cleaned the MAF sensor and my air filter is dry type.
If the fuel pump was dodgy, wouldn't it also affect the performance when I put my foot down because she still goes strong when the foot is flat to the floor.
Have booked it on at Tunehouse on Monday.
Hopefully they can find the problem
Cheers

[TD]

Read that TSB...seriously...more info is always handy to have