SES Codes:
18 - Cam/Crank Error
41 - Cam Sensor Circuit
58 - PASS-Key Fuel Enable Circuit

I have left these codes alone for about 8 months now and all was fine. Sometimes the light would be on, sometimes not. The only problem was when it was on, the car may stutter a bit to accelerate.

Well now i'm noticing that I am eating through gas. Granetd I have been driving more, but I just want to be sure this is related. So my question is:

Is it possible for my Cam/Crank errors to get worse and thus just now use more gas?

Also I will be keeping track of mileage and gas used so what is the average MPG that I should expect to get with my SSEi 1992?

Thanks!

Ignore the code 58. It'* a known bug in the 92 PCM.

Inspect the wiring harness for your cam and crank sensors. Both share a common connector underneath your alternator that migrates towards the front of the engine.
In this pic, you can see it. The connector is in the top right corner of the pic, and the wiring harness is the shinier black loomed harness going from right to left in the pic. The first 'tail' downward you see behind the water pump is for the cam sensor. The next 'tail' goign down is for the crank sensor, and the rest of the harness travels on to the ICM.





Ultimately, your crank and/or cam sensors are bad, and yes, that'll kill your mileage.

Your car should be able to achieve 28-30mpg well-tuned, with a trans that doesn't slip.

It wouldn't have anything to do with the magnet I have read up about?

Also if the cam and crank sensors are bad would that mean the part I would buy would be whats in that 2nd pic you posted? If so, how much am I looking at?