Horrible Gas Mileage

[Pontifex]

I am pretty sure my car gets 10-14 miles to the gallon, I know it is supposed to get WAY better than that. My car does idle a little rough, and shits weird, i asked at autozone, guy said throttle position sensor, and it could be idleing rough because the alternator.

Comments, suggestions?

[350F]

How many miles? Have you given the car a tune up?

[Shadow-D]

Is the check engine light on?

[Pontifex]

I have just hit 173k and about a week after i got it home, making at a daily driver, yes, the check engine light turned on.

idk, but its horrible

The check engine lights turns on about 5-8 minutes after i start it and drive it

[rixGAphx]

I have just hit 173k and about a week after i got it home, making at a daily driver, yes, the check engine light turned on.
The check engine lights turns on about 5-8 minutes after i start it and drive itInteresting.

That is when the engine has warmed enough for the ECM to switch from 'open-loop' to closed-loop', where it wants to adjust the FI according to the data from the O2 sensor.

If the ECM gets no data, or goofy data, then it reverts to fail-safe 'open-loop' where it runs ultra-rich to avoid the dangers of a lean burn.

After the car cools-down overnight, it's fat and happy and has forgotten yesterday.
Until it again warms, checks the O2 sensor, and says screw it.
Might also be the MAF or the MAP that is faulty, but the O2 sensor would be much more common.

Check the wire(s) to the O2 sensor.
How old is it? It was only intended to last 50-80k miles, so it's about due to be changed.

Would be great if you could get the codes scanned, but that's kind of tough on the '94.

Good luck,
-Rick

[Pontifex]

Wheres the o2 sensor? and What is a maf or map?

[Shadow-D]

I would check those codes anyway, OBD1 codes aren't as good as OBD2 but at least they will point you in the right direction.

O2 Sensor is on the exhaust below the manifold and before the Cat Converter.
MAF = Mas Air Flow
MAP = Manifold Absolute Pressure

[rixGAphx]

I would check those codes anyway, OBD1 codes aren't as good as OBD2He can't check them with the 'paper-clip trick.
His '94 GA, (and the '95) have OBD-1.5, which can't be read by old OBD-1 scanners, nor by new OBD-II scanners.
Only a more-sophisticed scanner, with the particular software AND with a specialconnector cable, can read his ECM.


MAF and MAP are sensors, that help the 'puter determine the density of the air so it can accurately inject the right amount of fuel.

Look at the throttle body.
There will be 3 or 4 devices with wire connectors:
* The Throttle Position Sensor (TPS), right at the back of the throttle shaft.
* A little can next to the thottle body, the Idle Air Control valve (IAC).
* The MAP: http://www.partsamerica.com/product_images/img/sta/as5.jpg
* A big square thing in front of the throttle body, the MAF sensor (you may or may not have one; Checker Autoparts has a listing for it, but my Chilton's manual doesn't show one).

[gt00]

The check engine lights turns on about 5-8 minutes after i start it and drive itAnd you continued to drive around wondering why your gas mileage was poor ? Check the code and you'll likely find out why . Don't rely on what some bonehead at Auto Zone says either .... :roll2:

[Shadow-D]

He can't check them with the 'paper-clip trick.
His '94 GA, (and the '95) have OBD-1.5, which can't be read by old OBD-1 scanners, nor by new OBD-II scanners.
Only a more-sophisticed scanner, with the particular software AND with a specialconnector cable, can read his ECM.

Ahh I didn't know that about the OBD 1.5 :( Sorry about that...

[Matt95GT]

Get the codes, otherwise speculating will waste money replacing the wrong parts.

[Pontifex]

Well ,what can i do aboutt the codes, none of the autozones or any parts store has an obd or obd or w/e 1 scanner. They tried the paperclip trick and it didnt work

[rixGAphx]

Most repair shops want $80 minimum to plug-in their scan tool.

Don't know about NE, but here in AZ Aamco Transmissions is running TV ads begging customers with SES/CEL to come in for a FREE analysis of the scan.

Basically, many SES/CEL's are tranny-related, so they have the opportunity to actually fix the repair if so indicated.
And even if the SES code isn't a tranny issue, Aamco wants to sell basic tranny servicing.

Their benchtop machine is prolly capable of reading your '94.

Failing that, you would prolly be better-off paying a shop for the diagnosis, rather than throwing money at AutoZone and parts at the car.

[Matt95GT]

http://www.gaownersclub.com/forum/showthread.php?t=83532&highlight=actron