98 civic LX 5spd. Used to get 300 miles to the tank, now only getting 200. Plugs look good, runs fine and no codes or pending codes. Last tune up about 4 months ago. Scanner readings after driving for 20 minutes in 75* weather are fuel system 1 CL --Calc Load 27.0 -- Ect 195 -- STFT B1 % 0 to -0.7 -- LTFT B1 % -2.3 --Map 7.3 -- Spark Adv 12 at idle -- Iat* 122 -- Tps % 10.1 at idle -- O2s B1 S1 (V) .29 up to .640 -- STFT B1 S1 % 1.5 -- O2s B1 S2 (V) .740 --stft b1s2 % 1.5 Please help if you can

 

With that tune-up, what all was changed with the Tune up? Last time air filter was changed? Fuel Filter?

 

E3 plugs, aem dry flo ram intake, timing belt distributor water pump wires intake gasket head gasket and valve job, fuel filter is about 7 months old, Honda fuel filter from dealer.

 

after driving for 20 minutes in warm weather, shouldnt my car have gone into open loop ?

 

replace t5he pcv you will be amazed ......and run some of that lucas fuel treatment in it that will help to ,..................and one last thing ive noticed take off easy it makes a big difference........................good luck

 

Always check / set the base spark timing with a timing light after replacing the timing belt.

You want closed loop mode in normal operation. Open loop mode is during warm up and gas mileage will be less. Seeing the ECT read 195 means it should be in closed loop.

 

Thank you.. Timing was set correctly using the jumper wire on the connector as well. Still wondering why my MPG'S went south with no performance loss or MIL lights..

 

I checked my PCV and its working. Checked dist. cap and it looks good. plugs look good. Have not checked fuel pressure yet. Is there anyway to see if my CAT is working properly ? It is an aftermarket one I bought from E-bay.. Also how do I check my O2 sensors correctly ?? Please help, MPG'S suck.............