my 1993 civic automatic is getting the worst mpg i have ever seen , it goes about 30k on 4 liters i have no clue what to do any help would be greatly appreciated .

 

Has it always gotten this?
Did you just get the car?
What changes have you made?
Have you checked the basics: Plugs, wires, cap, rotor, air filter, tire pressure, fresh fuel?

 

i have had it for 4 months it has always been bad , it also revs really high for a long time , and when i start it goes from 1000-3000 till it warms up , i was thinking ecu or pcv valve

 

Sounds like the FITV needs cleaning or replacing. Start there. Replace the PCV valve if you want as well. They are cheap.

 

would the fitv and pvc valve make the car slow down drastically when i take my foot off the gas and then speed up again without me touching throttle

 

Have you checked the computer for trouble codes?

Does it idle normal once warmed up? They are designed to idle fast when first started.

If the engine is revving really high before the automatic goes to the next gear, even if you are only pressing the gas pedal lightly, there could be a problem with the cable from the throttle to the transmission.

Wrong timing (cam or spark) can make the mpg very low. That will not turn the CEL on. Also you should make sure that all 4 cylinders are working by disconnecting the fuel injectors one at a time. You do need a steady idle for that test.

 

no trouble codes all spark plugs and cylinders are working what is the cam or spark timing you speak of ? i know very little about cars sorry

 

MY biggest concern is the terrible gas mileage ive checked every code and done a tune up

 

im willing to bet your IACV is completely clogged and needs to be cleaned. check youtube for DIY vids.

 

i cleaned the IACV and there is no differance any other ideas plz