Stomp Test Doesn't Work

[evil_twin]

Anybody ever have this problem? Alright, so I had a check engine light when I would come to a stop at idle. I bump the throttle and the CEL will go away. I figure it's the o2 sensor going bad. When I got home I did the stomp test, but nothing happened when I did the stomp test. I know I have done this test on this car before and it worked. I don't know why it doesn't.

So the next morning it had a rough idle then dies, I get to work and clean the o2 sensor. I tried the stomp test again, and it still doesn't work. I clean the o2 sensor, drive the car out. After work I start the car and it runs fine. So I turned it off, and did the stomp test once again and still nothing.

I get home run the Peake scan tool on it to find code: 0A - Emissions (Lambda) Control. My conclusion is the o2 sensor, but my question is... how come the stomp test doesn't work? I KNOW I am doing it correctly. Anybody have this problem before?

[Adrian_Visser]

The WOT switch in your TPS is probably dead, you can test it pretty easily with a meter.

[noE30]

I don't know about your problem but I had a issue last summer where my car had a rough idle and a cel, i tried the stomp test and it never worked either. The problem eventually corrected itself though so I dont know what caused it.

[evil_twin]

I'm thinking it might be the TPS WOT is dead too. We'll see, i'll get some more testing done tomorrow.

[sector6]

...doesn't work in my 89 325is either, but does in my ix.

[evil_twin]

yah, but it HAS worked before... lol thats why it's weird.

[jlevie]

If either the idle switch or the WOT switch in the TPS isn't working, the stomp test won't work.

Having the CEL come on at idle and go off when you open the throttle and having a Lambda fault strongly suggests intake leaks. The O2 sensor could also be part of the problem if it has 100k on it. The useful life of an O2 sensor is only 100k and the sensor should be replaced at that mielage as a routine maintenance item.

[evil_twin]

Yah. I really don't believe it's an vacuum leak because if it was a vacuum leak it should happen all the time (just about). I cleaned the o2 sensor, and the CEL hasn't come back. I think I'm just going to push it a bit more because a new motor is going to go in soon.

[jlevie]

I've seen this on several occasions and every time the cause has been intake leaks. So I'd bet on it being the case here also. The only sure way of finding intake leaks is to have a smoke test run on the intake.

[evil_twin]

I just put a new intake boot on not too long ago.

[jlevie]

That is only one of the potential causes of an intake leak. The complete list of possible causes of an intake leak is:

Intake boot
Throttle body gasket
ICV hoses & connections
Brake booster, hoses, and connections
Crank case breather hose
Evaporative control hoses, valve, and expansion tank
Fuel pressure regulator & hose
Injector seals
Valve cover gaskets & bungs
Oil filler cap
Dip stick o-rings
Oil return tube o-rings

While leaks in some of those can be found by inspection or by spraying carb
cleaner on suspect areas, not finding leaks that way doesn't eliminate the
possibility. Only a smoke test will really work.

[blocke]

This is interesting, as Ive suspected an intake leak for some time on my car, but cannot find it by the usual starter fluid spray test. Whats a smoke test consist of, and is there a home-based kit, or whats a shop usually charge?