>>>*One thing here I see over and over is a TPS problem. But once checked out and set they should work, still, I am guessing somewhere around a dozen cases of "strange stuff" that gets fixed when it is replaced are in my files.
The other interesting thing is a bored out throttle body. That point is not a restriction since the engine is only 2.4L and can only draw so much air, so all that could happen is RPM potential. Adding airflow potential certainly can help, adding too much always hurts.
*Combine a freer flowing intake with a freer flowing head/cam combo, then add a very nice 4 into one header and it all adds up to the ECU going "WTF??" at lower RPM's, unable to compensate for a velocity drop. ...Simplistic there but it can happen.
Then it is possible for the system to start "hunting" to try and find a balance, since once baselined she basically tunes herself..
There is an old saying that bigger is not always better, and when dealing with computers, just right is.....well....just right. Everything else is...just wrong.
Your description is mildly similar to some this old man has heard before except for being WAY more extreme.
Keep digging, this is getting to be worth a sticky....You could be helping a heck of a lot of folks here, including me.
*And yep! The wrong spark plugs will sure skip at different throttle settings...*EB
I don't know that I have the wrong spark plugs, but I am hoping for confirmation from others that may know in particular what these v-shaped electrode plugs do (or not do) to these 22re's.
I know I didn't need the bored out TB or the LC headers, but "I had to try them". Hee! Hee! I've had the headers since 2003 when the stock manifold got a big crack in it. Can't say the LC headers have helped the power, but I can't say they've hurt either. Either way, it's been way to long since I ran a "stock" system to know the difference.
I did notice that the bored out TB gave better throttle responce.
Side note: I don't know if this is normal, since I've never driven any other 22re's: My set-up makes very little added power past 1/2 throttle, and my vacuum gauge confirms that. Anyone care to comment? That's something I've been wondering about for some time.
Okay, here's what calmed the idle down. Now, I did a lot of reading in the archives to figure out what causes a surging idle, and it almost always came down to the TPS not set right, a bad IAC valve (or blockage in that area), a bad ECTS (or usually an air pocket in front of the ECTS needing to be burped and/or more coolant added), or the idle adjusting screw being set too far out.
I probably swapped the TB out at least 6-7 times to figure out what was going on. End result is that the IAC valve must have been letting too much air through even after it was hot and the piston was extended. This particular IAC valve I got off another vehicle when I purchased the TB as a whole unit. I did that because my original IAC valve wasn't allowing any air to pass through on cold starts.
Fortunately, the original valve still works after I cleaned it up and got the metal shavings out of it. I have a feeling it's still slightly short of fully functional, however, because I'm having a hard time bringing the idle way down like I should with the screw turned all the way in.
Now, another problem, and maybe one that people forget to check. As I already stated, I'm running a bored out TB. When the machine shop fitted a new throttle plate, they did "okay" but there were some gaps around the edges letting a little too much air through. Funny thing is I've been running this set-up for over a year with no trouble. For some reason it now wants to rear it's ugly head.
So, I filed down the spots that were too far extruded and not allowing it to fully close. I now have it to where it's as sealed as the other TB is that I have on hand. I then realized that in my case the linkage that connects the TB to the throttle parephenalia on the side of the intake plenum needed to be shortened slightly to allow the throttle plate to fully close. I noticed that the idle would stay in the 1400-1500 range unless I put pressure on the external throttle linkage, forcing it closed. Easy fix, and now the idle stays around 1000, which is plenty acceptable to me. But I wish I wasn't maxed out on the low side of the idle adjustment screw.
I consider myself fortunate that I had that extra TB with accessories handy. Otherwise, this could have been much longer and more painful. I did most of the usual stuff before trying this, such as making sure the ECTS, TPS, AFM were all working. I even pulled the ECTS out to make sure there wasn't some fluke piece of something blocking the sensor.
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Back to EB's comments above:
All this free-flowing stuff could very well be why I have that miss in one of more of the cylinders. I haven't verified it yet to be sure but I think I detected that the miss would subside quite a bit at higher rpms (3000 plus).
*Much thanks to EB and the others who helped me figure this out.
