I have found im getting low mileage from looking at some posts and I need some money so im wondering where i start to diagnose the problem so i can save a little. I'm getting probably 10-12 mpg right now and im supposed to be getting aroun 18 so where do i start to find out whats wrong with it?

 

well this is probably the most simplest of all but, did you check your filters? (Intake/fuel)

 

haven't checked fuel but i know my intake is good

 

BUMP!


I need to know!! how do i make it efficient. i need more money so i can get my car back down to having 12 mpg but with more performance

 

How many miles on the car?SES light coming on?Like said before change filters.Proper tire pressure.If its tpi it could be an injector or pressure regulator.How is it running?If you havent done it yet a good servicing and tune up will work wonders for a 20 year old car.

 

It's got 122,000. No SES light. Its TBI. Well i did you regular oil change with oil filter but no spark plugs or wires or anything like that.

 

Okay not sure but when i first got my car the guy had what looked like a heater hose connecting a port on the outside of the right header to a valve on the bottom of the intake...could that be it? i took it off cuz what i read said it was putting hot air into the engine...isn't that a bad thing? I don't want hot air in my engine do I? please reply i'd like to get a little bit better gas mileage

 

I got better mileage by going ot autozone and picking up some of those nifty silicone vacuum lines. Just replace all of them, leak or not. They are garbage stop. Once you have better vacuum you should have an all-around more efficient car. When you can afford it, do a complete tune-up with acdelco parts. I don't know why, but I had all kinds of diff brands on my ignition system including 12 dollar apeice iridium plugs. My car vibrated crazy. I got the acdelco and it's fine now. so I guess all the know it alls on this forum really know it all. lol

 

Don't forget to check parasitic drag on the car. Brakes dragging, wheel bearings under greased or too tight, and poor front end alignment can all lead to poor mileage. Also check the tire pressures. Don't want to put any bad karma on ya, but a slipping trans, or worn clutch will also kill the mileage.



Max

 

hmmm well sometimes when im shifting down from lets say second, it revs up like i let off the clutch (but i didnt). It only does it when i'm at higher rpms. Is that a possible slipping transmission? i dont really know what happens when the trans slips.

 

Change the plugs, wires, cap/rotor, fuel filter - use good quality parts, don't cheap out. Don't use platinum or any fancy plug, use the basic copper AC plugs. Check ignition timing too if you have the tools and know how to do it properly.

 

I had about the same problem in my 305... well, it actually turned out to be a .30 over and my 4 speed with the 3.23's weren't helpin much either. Changed my fuel filter, air filter, and a fresh oil change w/ filter. Increased mileage a little bit. Adam's right though, if you have the tools to check your timing, that may be a big contribution to the problem.

 

Diddo on this one. Also, what you described as the "large heater hose looking thing", strikes me as part of your A.I.R. emissions system. Please give us more info on your car. YEar, engine, trans, etc. Do you require emissions testing, either sniffer or just for them to look at? If you removed part of the emissions system without properly blocking it off, that would cause a huge drop in efficiency. Probably 5 or so MPG at least.

 

no its not air....it goes from the header to the bottom of the long peice thats goes off the air cleaner assembly....not sure if i'm explaining it right. i'll get a pic soon to show you

 

That's just to help the engine warm up, that definetly shouldn't be your problem.

 

ok wasn't sure about if i really needed it or not

 

Helps when the engine is cold, nothing more.

 

Ahh, looks kind of silver? It's the heat riser (pretty sure that's the name for it), pumps some hot air exhaust back into the intake to help it get warm as the other posters have already mentioned.

 

Doesn't suck in exhaust, it lets the air cleaner suck in hot air from around the exhaust manifold so it will warm up faster. There should also be a valve in the air cleaner to block it off once its warmed up.

 

Hmm...with the hole in the manifold like I saw when I removed it, looked like it would pull some exhaust.

 

No mine doesn't have a hole in it. just like adam said it sucks from around....thanks guys you're a big help....did anyone find that its hard to change spark plugs in these cars...i'm having the hardest time getting the ones towards the back of the engine....im thinking of taking it somewhere to get it done

 

It's especially hard to change the plugs with all of the emmisions crap in the way. I had to jack my car up to get at the plugs towards the back on the driver's side.

 

Plugs are a bitch in these cars, unless its a basically stripped engine like mine. I have no wiring to deal with anymore, no emmissions components, no manifolds (tube headers). It only takes me 15 minutes to do on mine now. My stock '97 LT1 car took me 6 hours though, LOL.