Possible Fuel Leak?

[broken_suave]

I was wondering if I could get some help. I have a 98 AU Futura Sedan.

The other day I put about enough fuel in the car to get to about 3/4 of a tank. The car had been running for about 5-8 minutes, and was still below normal range on the temp gauge. When I got back in, the DTE read: 166km (non revised, I didnt look at it until I got to where I was going).

I then drove into the city (30-40 mins max, heavy traffic) to arrive at my destination, with the temp gauge in its regular position between the N and the O in the Normal temp range. The DTE read: 152Km. Let it Idle for about 2 mins then switched off the car, and waited for my girlfriend to finnish work.

I then turned it on again, and the temp was in the higher end of the normal range on the temp gauge, so I let it idle for a bit, to get the coolant flowing, popped the hood to allow for better cooling. The guage dropped appropriately.

However, looking at the DTE, I saw: 138km. In the next few minutes driving home, it drove VERY conservatively, only to watch the DTE drop SIGNIFICANTLY quicker than it should. Comming to a halt at a set of lights I put the window down to see if I could feel excess heat from under the car (as the temp gauge needle was sitting just above R on the Normal range), there was excess heat, and I could hear the second thermo kicking in. I could also smell petrol. At this point, I looked at the DTE to find: 125, nope, 124.. infact 122 before the lights turned green (about 2 mins).

I had to get home, so I drove very carefully and conservatively. By the time I pulled into my driveway, the DTE read: 100kms. And the temp along the way home started to rise a bit. The thing is, it takes me 1/8 of a tank to drive into the city and back, however, this trip cost me a smidgen over 1/4 of a tank.

My long and annoying question is, could there be a blockage somewhere in the fuel lines, causing a leak earlier in the line, and starving the engine of fuel, causing it to lean out? This is my first thought.

I should also mention my rear muffler has just rusted off the U bend, and so is no longer part of the system so to speak. I'm getting a new system installed on thursday, but I'm wondering if this may also be having a negative effect on the ECU or some such.

I will be having a mechanic look at it, as soon as I can get to one. Easter was not the best time for this to happen :P Im just interested in your theories and responses.

Thanks in advance.