I have a 91 RS 305 with 91k miles on it, my mpg is progressively getting worse, I'm down to 12 mpg, Ive had the service light on because of the EGR a few times, it has died on me while driving and something does not sound right with the engine/tranny, I currently am laid off of one job and make minimum wage at the other (still in high school) so I don't have money to figure out why these things are happening, can anyone give some advice on what commonly causes these different problems?

 

put a 2x4 under your gas pedal. that may help things out for you.

 

I drive it the same way I did when I got it 9 months ago, and I was getting 17-19 mpg

 

whens the last time it had a tune up, oil change, trans flush?

 

replace the coolant temp sensor.

 

Is the engine getting up to 190*? If not, that most likely the problem, get a good 195* t-stat. I don't care what anybody says, a cold running efi engine does not get better mpg then a hotter running one does.
Is your air cleaner the stock type? Make sure the hot air tube that hooks to the exh. manifold is good. This aids in mpg in cold weather.

 

Transflush last summer, oil change 1500 miles ago, I change the cap and rotor and pulled the plugs and wires but they were still good, I have an open element air cleaner on right now and I changed the radiator and coolant and hoses last summer but not the thermostat (which I should have) but it never runs over 200, it's usually around maybe 180ish

 

Could be a bad O2 sensor

 

That's what I'm thinking, once I get back to work that will probably be the first thing a try

 

Put the stock air cleaner on for the cold months, get a new t-stat. 195* stat, 180ish is too cool.. Trust me on that.
Make sure the vacuum hose to the map sensor is good.

 

Yea I guess I'll put the stock one back on, but I don't have money or time for the thermostat right now, when winters over and I get back to work ill definetly change it if I still have this problem