Thread: Car running bad, unsure if trans or engine

Ok everyone. Mr 03 gt is running like absolute sh*t. It feels like the cat is clogged, but then again it feels like the tranny is toasted. Help me out here. I had one code showing but it was P0442, Unless I have a Vac line leaking, I dont know what it would be.

Technical DescriptionEvaporative Emission Control System Leak Detected (small leak)

What does that mean?This indicates a fuel vapor leak in the EVAP control system. It means a very small leak has been detected. In fact, the leak can be from a hole as small as 0.04" in diameter. The (EVAP) emission control system prevents the escape of fuel vapors from a vehicle's fuel system. Fuel vapors are routed by hoses to a charcoal canister for storage. Later, when the engine is running a purge control valve opens allowing intake vacuum to siphon the fuel vapors into the engine.

SymptomsYou likely won't notice any drivability problems.

CausesA code P0442 most likely means one or more of the following has happened:

A loose or improperly affixed gas cap
A non-conforming gas cap (i.e. not factory/original brand)
A small leak/hole in a fuel vapor hose/tube
Other small leak in EVAP system
Faulty vent o-ring seal
Possible SolutionsWith a P0442, the most common repair is to:

Remove and reinstall the gas cap, clear the codes, and drive for a day and see if the codes come back.
Otherwise, replace the gas cap, or
Inspect the EVAP system for cuts/holes in tubes/hoses
Sources: About.com

try cleaning the maf aswell to see if it runs better.

and if you think its the cat, pull the upper o2 sensor and put a pressure gauge in there and see what the pressure read with the car on, it should be less than 1-2 psi.

when I first bought the car, I drove it about a month and it threw that code. I found a pinhole leak in the fuel filter, replaced it, cleared the code. I never pump the gas with the motor on, and i always make sure the cap is tight.

As far as the MAF, Whats the best way to clean it?

Soak it in maf cleaner. It comes in a can from parts stores.

with maf cleaner

A clogged cat will make a transmission feel like its slipping.

I drove for about an hour, no codes hit. I'm going to clean the MAF tomorrow, amd make an appt. to get my cat replaced this week.

dont just assume the cat is bad yet.

You should do tests befor you just assume stuff.

take the upper o2 sensor out and take the car for a short drive, yes it will be loud like a tractor and will throw a code, if the car runs better when doing this test it show that the cat is plugged up because the o2 hole is open its letting all the gases that cant normally escape get out.

Ok, cleaned the maf and threw a new air filter in for sh*ts and gigs. Still not running right and no codes have hit. I'm lost here. I checked the trans fluid, it's not burnt and smells fine, but there are some bubbles.

again with the bubbles

Little ellaboration please

Air Bubbles in Transmission Fluid
There is usually one of two causes for air bubbles in transmission fluid. First, your transmission fluid level may be too low. A low level of transmission fluid will cause the pump to suck up air with the transmission fluid and the result will be air bubbles or foam seen in the transmission fluid when checked on the dipstick. The second most common cause for air bubbles in the fluid is that there may be too much transmission fluid in the tranmission. Too much fluid in the transmission pan can be remedied by draining out some of the fluid. Some vehicles do have drain plugs like an oil pan, but with most vehicles you will have to remove the transmission pan to lower the level of fluid. If your vehicle does not have a drain plug and you plan to remove the pan to lower the fluid level, you may as well change the transmission fluid and replace the transmission filter. Or if you don't want to do it yourself, take your vehicle to a reputable repair shop and have them do the fluid and filter change for you. On most vehicles, changing the transmission fluid and filter is not a difficult task. If you do notice air bubbles in your transmission fluid, make sure you take action immediately as either of the causes above can quickly cause severe wear to your transmission parts.

Source:Air Bubbles in Transmission Fluid via google.

Thanks Spade. I've checked the level and it's where it needs to be. So complete drain and new filter?

A filter and fluid change should help you out. How is the consistancey of the Transmission fluid? If it's kind of watery you could have another issue all together.

The fluid looks, smells and feels perfect. I dont know if this matters, but I charged the A/C about a month ago and noticed it started acting up. Could just be a fluke.

Yeah, that should be completely unrelated.

Try the filter and fluid and while you're doing it, see how much crap is built up on the magnet. If its chunks... You might be looking at a new transmission.

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FIXED.. It was the cat. My car has never ran this good.