93 Legacy Turbo (Estate) - poor starting

[fopetesl]

Serviced regularly but in the last 2K miles starting has become more
difficult.
Local garage phoned Subaru main agent who suggested may be leak in
exhaust or inlet manifold.
Exhaust is S/Steel with no blowing anywhere.
Definitely NOT a Lambda sensor since engine light should come on, they
say.
Sometimes it starts OK, sometimes have to churn over for several
seconds until it catches.
Runs and pulls fine except MPG gone up to 25/imperial gallon (from
26.5 local - 29 long distance).
Have had the car 10 years so know it well and have looked after it -
nearly pristine.
Oh, and the battery is just fine.
Anyone had this problem before?

 

[Bob's Backfire Burrito]

Serviced regularly but in the last 2K miles starting has become more
difficult.
Local garage phoned Subaru main agent who suggested may be leak in
exhaust or inlet manifold.
Exhaust is S/Steel with no blowing anywhere.
Definitely NOT a Lambda sensor since engine light should come on, they
say.
Sometimes it starts OK, sometimes have to churn over for several
seconds until it catches.
Runs and pulls fine except MPG gone up to 25/imperial gallon (from
26.5 local - 29 long distance).
Have had the car 10 years so know it well and have looked after it -
nearly pristine.
Oh, and the battery is just fine.
Anyone had this problem before?

Intake manifold vacuum leak. Check ALL hoses on top of the engine as well as
hose to the power brake booster.