Ok, I have a 1991 ranger 2.3l with the 5spd and i only get 14.8 mpg at the most. I have ran seafoam through it, replaced all 8 spark plugs and plug wires, cleaned up the mass air flow sensor, put in a new idler, did a cylinder leak down test(i got 80% leakage on cylinder 3) and ran a diagnostics test. on that i got a code 63 which had something to do with wires that plug into a sensor in the intake, but i cant get to it inless i take off the intake manifold. other than poor fuel milage the truck runs good aside from the ocassional sputtering when accelarating and when i first start it, it goes back and forth between 700rpm to 1200. Any ideas on what might be going on?

 

Have you replaced all the filters such as fuel, air. your 02 sensors could be bad. Don't feel bad about your mpg I think I still hold the worst mpg on this site 10.7 mpg.

 

Dirty/worn injectors
Old/streched timing belt and tensioner
Weak valve springs
Bad fuel pressure regulator

Have you tried disconnecting the battery cable for 15-20 minutes to let the ECM relearn its settings ?

 

I replaced my air filter but not the fuel, The o2 sensor is the one thats fried onto the exhaust, right? 10.7!? how are you getting that? i guess my big concern is im scared of there being a bigger problem(3rd cylinder) and i want to try and catch it before it gets worse

I didnt think of any of those, i have had my battery disconected though


Thanks for the help guys.

 

try some restore it should help the comprisen problem you have i have used it on all my car and it help

 

do you run restore through your fuel tank or straight through the injectors on the common rail?

 

nevermind, found there website. thanks

 

for under 10 buck it worth a try and put it in your oil

 

Restore will only mask the problem , not cure it.

 

well i had a buddy pick up a can for me already so ill see what it does, i hooked up that scanner to my truck again about an hour ago and found out i need a new throttle body sensor

 

http://www.fordfuelinjection.com/?p=30 says:

"The TPS sensor has a great deal of influence on the fuel ratios and timing curves, because the TPS is a user interface sensor. The TPS is the closest thing you have to a phone call into EEC."

Replace yours. Your gas mileage should improve.

The hunting idle could be a bad IAC. Clean it or replace it. When you have it off, look at the gasket. Many have improved their idle by making a new gasket with a smaller hole.

It sounds like your IAC isn't working. If you disconnect its electrical connector with the engine running, the idle should change. If nothing changes, it isn't working. Could also have a vaccum leak affecting idle and MPG. Spray carb cleaner around the intake, vaccum hoses/connections (including brake booster line) and listen for idle changes.

 

Thanks alot guys, I was really lost on all this. i did do a test for vaccum leak though and it was good, ill look up the iac tonight and i was planning on getteing the tps tomorrow while im at autozone. ill be sure to post back once i have replaced it all. thanks again

 

nope i get around 8-9 mpg!

 

dang. well never mind I guess I don't have the worst mpg on R-F

 

Ok, i bought a new TPS, and had already put a new IAC on it when i got it, but it didnt do anything. So i put it back on the scanner, did a Key On Engine Running test, and found out something was going on with the EGR. I pulled it off, and chipped off a nice thick layer of carbon. after that i rigged up a manual vacume system and found out the valve won't move. so i think i found my problem. but hey, thanks for all the help guys, i was really lost.

 

Yep

 

I had similar problems in my 89, 2.3, I replaced the Air Idle Control valve first and it fixed it for a few days, then problem started again, then i changed the Throttle postion Sensor and it fixed it all! Good Luck

 

he found it. if the EGR isn't moving that's probabaly where all his problems are coming from, especially if it's stuck open.

 

well i bought a new egr valve and put it on the other day. i havent ran a full tank through yet but i dont think that was my fuel mileage problem.

 

you still getting that code 63?

 

I haven't checked it yet, i've just been waiting to run a full tank through. i really need to put it on the scanner and make sure its ok.

 

that weak #3 cylinder is what i would be worried about. i would say that is what you need to fix.... or run it till it blows up and then it will be fixed with a new motor. i just think that you are only running on cylinders 1,2, and 4 right now and cylinder number 3 is not working correctly and that is where you are loosing your fuel milege at.

 

ya but how would i fix that third cylinder? I have no clue as to what is causing it.

 

nah....i officially hit 8 mpg the other day when i filled up
if i find the receipt i could prove it....

when i usually get about 16 in the city and 24 highway

stupid cold weather

but i'm also not fuel injected.....and that hurts a little too

 

if it were only running on 3 cylinders you'd know. it's idle like crapola and have a huge lack in power. have you pulled plugs to see what they look like? could be a bad FPR.