Rage!!

[SirNemesis]

its the air intake temp sensor getting heat soak from the extracters. happened to my ss, ran for months and once the weather warmed up the same prob happened. my car was also tuned which exageratted the prob as it was running 22* advance. fitted up an otr and relocated the iat sensor and the prob never appeared again.

took a fair while loggin it on vcm suite to get it to show up as the day i took it to my tuner was cold n overcast. it was pulling all the timing in one hit. would only happen if the car was sitting in the hot sun for a while or the car was idleing for over 30 seconds. once up to speed the natural airflow cools the sensor and all is good in the world. so id say get an otr and tune and relocate the sensor.

if you want to test my theory pull the sensor housing out of the intake duct and run it ove the radiator cover to the hole in the corner behind the left headlight and pop it into one foe the slots and run around for a few days. just make sure you block off the hole in the intake. when i did this it still had the problem but very rearly which to me indicated that heatsoak was the prob.

This is a pretty common issue with poorly tuned MAFless cars, but wouldn't be an issue with a standard tuned MAF car. The IAT is designed to correct fueling / pull spark as temperature rises, this is its purpose.

 

[soop]

Yeah it didn't do anything anyway.

I've tried that. Tried the MAF. Didn't work.
I really reckon its something to do with the idle control. It still spins up hard going 1st to 2nd. So it's not lacking power.

 

[SirNemesis]

Years ago my car did exactly this, and I tried everything to fix it. In the end the only solution for me was to put the car in full open loop (disable o2 sensors) and dial the VE table in perfectly. No amount of new o2 sensors could fix the problem.

This was visible for me in the EFILive logs with STFT's slowly creeping up at the lights, and while creeping up the car would start to rock and buck. Once they maxed out, they'd return to normal and the car would idle perfectly for about 15 seconds. Then the STFT's would start to creep up again, repeating the problem.

 

[soop]

Ahh that sounds like a prick of an idea.
What causes it?

 

[SirNemesis]

If I knew, I would have fixed it instead of disabling the o2 sensors

 

[soop]

Haha, Is it a PCM issue?
If so, might be easier to get a mail order Mafless tune and replace the PCM.

Other thing I've thought about, could the little idle control stepper motor in the TB be playing up?

 

[SirNemesis]

I changed the PCM and loom with mine too, still didnt fix the problem, but it might be the problem with yours, hard to say.

Usually if the IAC is playing up you'll have larger swings in RPM, stalling and idle hang. Certainly worth trying another one though, but you may need to do a PCM reset to relearn its position. Non-genuines are available on eBay pretty cheap.

 

[Not_An_Abba_Fan]

Check your plugs, you have to remove them to fit the extractors and it is very common to crack a plug.

 

[soop]

Yeah I've seen them cheap. Might give it a crack.
That Fuel trim issue sounds bizarre, possessed car!

The car really feels like its going to stall at times, untill I boot it in the guts, I've seen the tacho fluctuate a couple hundred rpm while cruising at times. But its sort of to random to really say.
For a few bucks I might as well try it. Will probably have to get a bloody torx bit too while I'm at it. Shitty bloody things they are. Edit- Just bought one for $45, see how we go. I'll be stoked if this fixes it. Can't see it being a drastic issue because the car pulls like a 13yr old school boy otherwise.

Abba - They're new plugs since I fitted the extractors, as are the leads.

 

[Not_An_Abba_Fan]

Did the issue start after you did the exhaust? How long after that did you do the plugs?