Wish I could help you out more and i’m sure you’ve already done this stuff but maybe double check this out. Idle and timing setup.
1.) Warm Car up to Highway Driving Temp
2.) Turn off Car
3.) Lower Throttlebody IDLE screw to minimum (Do not Bottom Out)
4.) Disconnect TPS
5.) Start Car
6.) Observe IDLE RPMS
7.) Turn off Car
8.) Raise/Lower IACV depending on level
9.) Repeat steps 4-7 until IACV set to 850 +/- 50rpm
10.) Plug in TPS
11.) Start Car
12.) Adjust TPS to .455v using a voltmeter on the middle pin
After the motor is warmed and idle is set, you need to unplug the TPS and hold the revs over 2k for 2 mins. Then you need to race the motor 2-3 times over 3k to get the ecu into timing mode. From here you can use the black loop at the back of the valve cover for the pickup on the timing light. Sometimes it takes a few tries to get it into timing mode. When out of timing mode, the ecu will naturally advance the ignition to around 34-40 degrees in certain idle situations, which means you weren’t in timing mode. If you shoot the light and find it way out again, do the 2 min rev and race it 2-3 times again til the timing marks stay rather still without jumping back and forth when you move the CAS.
I can’t say for sure myself, but it is possible it is missfiring causing it to show rich instead of running rich causing it to misfire. It shouldn’t misfire running at 10 to, mine doesn’t at least. It will be down on power and all that but not like you unplugged a coil pack here and there. There would be a notable difference. You should unplug the coilpacks when it screws up and try to narrow the symptoms down like that. If it were infront of me I could probably say whether the chicken or the egg came first.
Usually, yes, but it is entirely possible it is shorting/not shorting so quick that it gives you the result you see. Again, you need to check the signal goin TO the MAF and ground while it is acting up and not. It doesn’t take much of a leak for it to runs like ass and be all screwed up at idle. I would pressurise the system and check for leaks, don’t assume there are none because there weren’t before… couplers get ripped during installation and can open/close with engine movement. Maybe not likely but it’s possible and you would feel pretty dumb if it turns out to be that simple. 15 min of work to eliminate 15 hours of searching for another problem…
MAF to SAFC yes. SAFC to ECU not necessarily. You need to compare the signal at both ends. Maybe there is a bad connection between the SAFC and ECU causing the ECU to get false values, intermittently, while still showing a steady value on the SAFC. I would almost bet it is something like this. You can’t leave any stone unturned like that, especially for another 5 min check AT THE ECU.
You can eliminate all the sensors (MAF, CAS, TPS, ETC) themselves in under an hour I would say. Only a handfull of them even matter at idle, at least enough to make it run that bad. Example: Don’t even bother with the O2 sensor, it simply doesn’t have that much control of how it runs.
Once you check out the sensors themselves (or change them when possible) get more and more into the links between what the ECU sees/puts out.
It has to be there somewhere… If you find yourselves changing shit in a desperate attempt to fix it stop and regroup. That separates the people who can diagnose shit from people who just change things because “they have seen this exact same thing before” and want a quick glory.
The coil packs might be working fine at idle like rpms, but when they are asked to do more work, they could be breaking down or loosing their potency somehow??
I’d suggest unplug any sensor temperature related, and the o2… might as well unplug the idle controls too…
that way the ecu has no adjustment feedback besides the afm… then you can keep it idling by cracking the throttle open either with the foot or screw
see if the results are more consistent, obviously if they are still wonky and jump up and down then everything you just unplugged is probably functioning just fine and you’re down to hardware things like cas and coils and such