HELP! Excessive gas consumption.. :( [Archive] - GrandAmGT.com Forum

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tido_29
08-19-2005, 07:06 AM
So I have been having bad gas consumption problem for a while now. But this past weekend was just ridiculous.

I went from houston to Galveston (about 44 miles one way).. well went to the beach (no driving down there) and came back home..

probably a total of maybe 99miles or so. Well I wasted HALF A TANK of gas.. I dont know what could be wrong??? :(


I have:

1) changed the fuel filter
2) checked tire pressure on tires
3) changed spark plugs maybe a month ago (not wires though)
4) added the fuel additives to clean the injectors..

Any help guys..
Redfox said a while back that my Fuel pressure regulator looked like it was going bad. Could that be the reason??
Please help guys!

RamAirGT22
08-19-2005, 07:24 AM
Do a search. There are a few topics on this subject lately. I know I saw some that said something about the clogged cat and whatnot...

tido_29
08-19-2005, 07:33 AM
I have been.. i did a search a few days back and after that again. :(

Any good search key words for a search.

redfox
08-19-2005, 08:15 AM
Hey Fausto, I was in Galveston this weekend as well on the seawall. Saturday. Do you have a gas smell? I know when they changed out my intake manifold gasket they messed up an o-ring on one of my injectors that was causing gas to pour out onto the ground. The regulator would only leak a little. Is your car running rough? that is some bad gas mileage. Do you have a bad smell coming from your exhaust?

tido_29
08-19-2005, 08:28 AM
No, the car seems to be running fine. And I dont smell any gas leak or anything :( Where is the pcv valve at?

Do you think bad O2 sensors could cause it?

redfox
08-19-2005, 08:33 AM
the gas has to be going somewhere. I mean your engine can't be using that much gas. you are running way to rich if it is and i would think it was run different.

atc3434
08-19-2005, 08:47 AM
A bad o2 sensor could defintely be at fault. I would check into that.

tido_29
08-19-2005, 08:58 AM
I am going to check for leaks in a bit but how do I know if the O2 sensor is bad? And how do you remove it??

I dont think I am running rich sine the car runs good. Doesn't really struggle or anything like that.

atc3434
08-19-2005, 09:39 AM
Running rich wouldn't show itself much, other than gas mileage and slightly degraded performance. When you mat the pedal, the o2 sensor doesn't contribute to the computers decisions about the air/fuel mixture, so you wouldn't be able to tell by how well it performs. Check the exhaust and back of the car for excessive carbon buildup, thats a telltale of a rich condition. A scantool could also be helpful in diagnosing the problem, if you have access to one. Changing the o2 sensor requires a wrench, and disconnecting the wiring, which is an easy wiring harness. However, its a pain to get to, its on the rear exhaust manifold. I would remove the coil packs, this might give you enough access to get it out.

tido_29
08-19-2005, 09:49 AM
thanks guys.. I will do these checks as soon as I am done w/ my lunch.

tido_29
08-20-2005, 04:00 PM
I performed the test where you attatch a meter (PSI) to measure pressure.

Well followed the procedures to release the pressure for accurate reading.

Then turn the key to "ON" and it read 60PSI.. when the book says it is suppose to be at 41-47PSI..
the book then says if the reading is ABOVE then there are two things to look at..

1) a blockage in the return line
2) a fautly fuel pressure regulator

Guess it was the FPR all along... i hope :(

Metallman56
08-20-2005, 08:56 PM
also you might want to make sure your wires are ok. escpcially if you have burnt through a couple. i installed the other guys headers and my gas milleage went way the hell up, also borla exhaust. after a few weeks it went way the hell down. i got new msd wires and spark plug boot pretectors and gas milleage went right back up. try that. also if your o2 sencer is bad you check engine light should be on. hope it helps. also i hope you didnt install bosch platnum plugs they are known for random misfires. also check the air filter.
good luck hpoe it helps

tido_29
08-21-2005, 07:56 AM
Well I did install bosch but I have been using them for a while. I will check the wires today too.. I remember I had burnt through 3 of them last time because they were touching the block.

mcgrady
08-21-2005, 04:00 PM
also if your o2 sencer is bad you check engine light should be on.

Not necessarily true. I've seen O2s that are giving bad readings but aren't picked up by the PCM as being bad.

bigtard
09-01-2005, 09:37 AM
I was having a similar problem. My battery and alternator died. After I replaced them, my gas mileage went back to normal.