Check Engine Light on during idle - Off when throttle cracked - stomp test no workie.

[Snowmann]

As the title states, after warm-up (out of the blue on the temp gauge) the CEL comes on. If I crack the throttle, the light will go away, but once 5-10 seconds of idle go by, its back on. If I shut the vehicle off, and try to perform the stomp test I get nothing, (I've done it before I know the proceedure...)

Things to note: I have a push button start, I have a switch that takes the car to the run position, then a push button to bump the starter. I don't think this would be any different then shutting the car off normally? What I'm getting at with this is am I by chance resetting the code when turning it off?

Not sure how to go about this and read the code, and/or diagnose...

Nothing "jumps" out on me when going through items on the car... sensors are in, new fuel filter, 173 ECU, nothing "wild" from an eletronic sensor standpoint...

Let me know guys!

[jlevie]

The stomp test isn't working because the TPS is bad.

That behavior of the CEL points to intake leaks, perhaps aggravated by an aged O2 sensor. The useful life of an O2 sensor is not more than 100k. If that applies, replace the sensor and have a smoke test run on the intake to find leaks. Oh yeah, and replace the TPS.

[Snowmann]

Could the TPS in itself be tripping the CEL?

I dont have any idle issues or for that matter and performance issues that point towards a vac. leak. The car idles fine, not high, not low, not rough... I did some poking around but a lot of the vac hoses were replaced when the engine was out, and didnt have this problem until recently...

Would my only means at this point to check the code be with a flash tool from like Peake?

[Snowmann]

On another note, I know I have swept the TPS for resistance before... would this be a sure way to rule out the faulty unit?

[IminDiegoTriick]

this is happening to me. it broke my dreams of trying to get my car smogged. neeed a solution. getting my car back from my mechanic for a full and complete tune up. i wanna try swapping o2 sensors and installing my new magnecor ignition wires combing with my ngk copper spark plugs.. hopefully it works!! how do you test for vacuum leaks.

[jlevie]

The only sure way to find intake leaks is to have a smoke test run on the intake.

[Sagaris]

On another note, I know I have swept the TPS for resistance before... would this be a sure way to rule out the faulty unit?

The TPS in the E30 is simply a full throttle switch and an idle switch with nothing in between. There should be continuity between the left and middle prongs at closed throttle and between the middle and right prongs during full throttle. Test it multiple times, they can be intermittent and fool you if you just test it once.

Keep in mind that the adjustment could prevent either of the switches from being engaged so the next step after a negative continuity test would be to remove the throttle body and test it off the car when you can adjust the position of the switch.

[jrobie79]

Same thing on my car, howver when I do the stomp test iget the lambda code, forget the numver maybe 1221? Either way I think it has to do with how rich/lean its running, I think mines a vacuum issue but im not really sure at all