DREAMZ28

iTrader: (1)

How's it going LS1Tech.



So, I got my Trans Am on Saturday for 6350 with about 101k miles on it. Pretty good catch IMO. They maintained it well and have the records to show for it, and just changed the motor oil last month. Bone stock besides Flowmaster catback and a K&N Air Filter.


Now while I was driving around yesterday with my mom, we had the windows down because off good weather. While driving we noticed we could smell fuel whether idling at a light or under light-medium throttle, it's always a notable smell. On top of that, the car went through about a 1/4 tank of gas driving about 40 miles so something is definetely off..

It can't be a leak because the car leaves no spots where it's parked so maybe a spark plug and I'm running on 7 cylinders? Would that cause the car to run soooo rich that I go through a 1/4 tank that fast?




Also, the tranny shifts a bit hard, not really a problem to me but could be smoother, would a fluid swap fix this?

BlackScreaminMachine

iTrader: (17)

If you have a missfire the dash light for Service Engine Soon (aka SES) would be flashing. I would have the PCM scanned. Free at autozone to see if any codes come up.

WOuld not hurt to do plugs and wires, and filter change.

Start there.

DREAMZ28

iTrader: (1)

Ok, but wouldn't the check engine light come on if the PCM was throwing codes?

mike171562

iTrader: (4)

Does your car have cats? any mods?

DREAMZ28

iTrader: (1)

Yes it has cats, the owner told me the only things aftermarket on the car is a Flowmaster exhaust that goes up to the cats, and a K&N air filter. Nothing serious at all.

I test drove a Camaro z28 the weekend before and honestly the Trans-Am feels a bit down on power compared to it. Trans Am's have the 2,73 rear right? I'm sure z28's do too.


I'm hoping some regular maintenence will clear this up

DREAMZ28

iTrader: (1)

Any thoughts on the transmission?

z28clark

iTrader: (2)

Is it a hard harsh shift or a crisp and quick shift? Possible that it has had a shift kit installed or pcm tuned to firm up shift points.

RPM WS6

iTrader: (3)

Are you smelling raw fuel, like an open gas can, or just rich exhaust?

I wouldn't be too concerned about gas gauge movement in partial increments like that. Fill it up, reset your trip meter and drive normally until you run the tank down to at least 1/4 tank, and then refill. Now you will know for sure how many gallons you used for exactly how many miles, and whether or not it falls within the "normal" range.

If it was a fuel vapor leak then it wouldn't leave a spot, but if this was the case then you'd probably be getting an EVAP code unless the leak just started.

If a cylinder was completely dead, you'd have a serious misfire and definitely be getting a code and SES for that.

I noticed that you mentioned a K&N filter. Sometimes people over-oil these filters, and that oil gets on the MAF wires. This can cause all kinds of little issues with driveability, including some weird shift behavior, MPG reduction, performance reduction, etc. The first thing I would do with this car is check and clean the MAF before worrying about anything else.

2.73 was a standard rear for all base model LS1 A4 cars, with a 3.23 rear being optional. The 3.23 rear was a required option for the SS/WS6 cars with an A4 though.

You can tell which gears yours has by checking the SPID sticker on the driver's door jamb. If you see the code "GU2" then it's 2.73s. If you see "GU5" then it's 3.23s.

DREAMZ28

iTrader: (1)

Z28Clark: It's actually gotten better lately, when it shifted before it would lunge forward hard enough to make a passengers head jerk back a little. It'd also almost hesitate to shift, as if it's trying to hod the rpm's up.

RPM WS6: Thanks for all the info! Under all throttle conditions it smelt like raw gas was spilled. Now I can only smell fuel under moderate-full throttle.

I'll change the filter along with the plugs and wires this weekend

SOMbitch

iTrader: (8)

DO THE MAF LIKE RPM SAID!!!!! Just get MAF or electronics parts cleaner and spray the **** out of it. DO NOT TOUCH the two little wires. The are fragile but that is the part that reads airflow....

A poor reading MAF can cause several of your symptoms....

ScottyBG

Have you checked the PCV system on this car? The rubber on it is normally rotting off them at about this point. If it has not been replaced yet it probably should be, that's very likely what you are smelling. The rubber hoses get cracked with age, and you get smelly crank case fumes comming out that should be getting captured and burned through the intake. I bought my '98 back in December, and it had that exact problem. I did a little research and found it to be very common. The parts to fix it are somewhat pricy, and not easy to get at they run behind the intake manafold. They will run you about $100 from an online source or about $140 from a dealer. You could also make your own from 3/8 fuel line, but I chose not to, I wanted to keep mine looking OEM.

DREAMZ28

iTrader: (1)

Ok cleaning the MAF will go along with my plugs and wires then, thanks for the tips


And yea I think I've heard about that problem yesterday when I was doing my reading, I'll have to give it a look Friday when I get back to the car.

FIVEPOINT7

iTrader: (2)

What is a "normal" range for these cars? Driving around town I get just under 14 MPGs and I had just learned to accept it. Is that low or about right? (Sorry OP, not trying to jack your thread.)

RPM WS6

iTrader: (3)

Well, normal will depend some on any modifications, trans type/gears, and also driving style. Depending on circumstances, 14 could still fall within the normal range for pure city driving.

My A4 2.73 '02 car usually gets somewhere between 16 to 18 MPG in city traffic, depending on weather. I've seen as low as 14.x before, but only in the worst combination of conditions. This is a stock car other than an air lid and aftermarket muffler. I've never done 100% highway driving with this car, but with mixed driving I've usually seen anywhere between 19-24+ mpg (again, with weather having some effect).

wicked383lt1

I had a similar problem and just changed the front right o2 sensor. First see if it's throwing any codes. That should fix it if that's the issue your having.

FIVEPOINT7

iTrader: (2)

I have a lid, headers, 160* stat, and magnaflow exhaust. It always comes in at 13.7 for pure city.
EDIT: A4 3.23 Torsen rear

RPM WS6

iTrader: (3)

Has the car been tuned for the headers? That might be effecting mileage. Also, the cooler engine temps of the 160 stat might be reducing mileage some (especially if you have matching fan settings and/or have been driving in cool weather).

I think the lowest pure city mileage I have ever seen under the worst possibile set of conditions was in the 14 range. Normally it's 2-4 MPG higher.

DREAMZ28

iTrader: (1)

Well lately everything has been going fine, no fuel smell unless I get heavy on the throttle.

usafws6

iTrader: (10)

Sounds like a typical stock tune. Its rich from the factory to keep people with heavy feet from burning holes in pistons. Put a wideband on it to confirm.

FIVEPOINT7

iTrader: (2)

No, the car wasn't tuned after the headers, and it made those numbers before the stat went in so I don't think that affected it. It might just be that it needs a tune, but I'm not bothering with that until I do some more mods.