Help with Celica not Running

[sarsippius]

I have an '01 Celica I'm having problems with.

Heres what its been doing before today:

When I get gas, whatever amount, it runs extremely ruff for a few minutes. Once I get going it settles down and runs fine. That is the only time it has given me any trouble. This would be in addition to fuel injector cleaner. I have had a check engine light that comes on at times. When I've had it checked, it comes back as a catalitic converter. I've had the catalitic checked, and it wasn't clogged.

Heres what it did today:

It was running fine all day, then I got gas. For some reason it would not stay running; I would start the car, and die almost immediately. Unfortunately I have to drive 30 miles for work, so I was able to get home. However every time I stopped, or had to slow way down the car would die. When driving I would feel the car "buck" a little, but I didn't have any problems getting home, as long as the car was running faster than 2000 RPM. I am fairly sure that the gas tank is under pressure when running, so I bought a new gas cap to see if that would fix the problem. It didn't help at all. In fact this is the first time I've ever heard it backfire.

So now I am trying to determine what the possible problem may be. I am thinking that it may be a dirty fuel filter, an O2 sensor, timing, or ignition.

If anyone has any suggestions, any help would be greatly appreciated!

Thanks in advance!

[bbmx952]

Does it sound really loud at all? Any overheating at all? You said you had the cat checked. I believe there are 2 of them were both checked? Also see if you can pull a code again.

[Boxedin]

You mentioned fuel injector cleaner. There is a possibility that the injector cleaner dislodged some foreign matter in the injector and is causing it to spray erraticly. If you can get it to idle and if its acting up, disconnect one injector at a time. The engine should really struggle if you do this but it should remain running. If there is no change in the way it runs, you found a bad injector. or you could do a resistance test on the injectors with a multi-meter or a fluke meter. I do not know the specs off hand but you could easily obtain that from your local Toyota dealership. There are a great deal of things that could be causing this problem. Even though you had the catalytic converter checked it may not be a bad idea to get a second opinion. catalytic codes are usually correct.

To address your other concerns, the fuel filter is in the tank and non-serviceable I believe. The o2 sensor would almost certainly throw a code. This vehicle has direct ignition so that is not too probable, unless you have a bad ignition coil, this can also be checked with a resistance test. Timing is controlled by the computer, and variable valve timing is contolled by a solenoid on the end of a camshaft, the likelyhood of this being your problem is also very small. Let me know if I can help further.

[sarsippius]

Here are the codes I got when I hooked up a reader:

P0171 - System too lean
P0100 - MAF or VAF circuit malfunction
P0101 - MAF or VAF CKT range/perf
P0110 - IAT sensor circuit malfunction
P0420 - Catalyst efficiency below threshold (Bank 1)
P0441 - EVAP emission control system purge flow fault
P0171 - System too lean (Bank 1)
P0441 - EVAP emission control system purnge flow fault

With that, everyone I've asked about it thinks its a MAF sensor gone bad.

Thanks for your help!

[bbmx952]

I would start with the MAF sensor, I have heard of these things gettin dirty and they just need cleaned so you might try that before you go get a new one.

Surging issues on a 2001 GT

[sarsippius]

I replaced the MAF sensor, but I'm still getting the same result. I guess the next thing is to replace the pre-cat O2 sensor?

[sarsippius]

I figured out what the problem was. Bad vac line.

Thanks everybody for suggestions!