Hi, Sorry to hear that, Bro. Running a High Octane Tune on low Octane can affect things adversely-moreso if you romped on it when the 87 was in it? Good news if Plugs are not melted, Knock sensor did its job. It may/may not be coincidence that you started having issues, here. Do the things that cost little or nothing first, but buy Plugs and swap out your Fuel Filter, buy CRC MAF Cleaner (if not already). Does it do this before Engine is fully warm? Try that AFTER you do the below- check your Coolant first, however. I think the issue may be getting ready to fully reveal itself via CEL.
It’ll be found either way. Read, first- prioritize, then start with these suggestions,
1) Try turning your Traction control off, or on- opposite of where it was. If you have Modes, try using another selection.
2) Change your online Fuel Filter. If you can get a rubber line on it, hook up a gauge and test Fuel Pressure (Scanner will also show this). Borrow a Fuel Pressure Test Kit/ Gauge from Advanced
if you can’t get a line on it.
3) When possible- Install a FP gauge on the rail, it’ll help you later, as well as now.
4) Datalog a drive with a drive cycle with your Scantool, if yours cannot- Advanced Auto will likely let you use theirs for one, look through Sensor Data for pegged Sensors, I.E. O2 Sensor(s) not correcting, Fuel trim, etc. Valuable information. More on bottom.
5) May be a weak/failing Coil, hard to test an intermittent one aside from swapping them to different Cylinders, it may be ok in one Cylinder- borderline in another. Label original Position with a sharpie with current position. Aside from a visual or resistance test with a VOM, intermittent Coils are difficult to test, unless you have a high-pot meter.Aftermarket ones usually prone to issues. Could buy 1 OEM and move it around to different Cylinders.
6) Change your Plugs. If not OEM- Replace with oem.
7) If you visually inspected the MAF, didn’t clean with CRC MAF cleaner, do so. Clean the entire Throttle Body, CAI internally, butterflies, everything with the MAF Cleaner. Clean air Filter(?) if not- Clean or Replace.Change PCV Valve.
8) Change your Oil & Filter with a Motorcraft,
K&N, or Mobil 1 Filter.
9) Check your Charging System, all Wires, Clean Battery Connections, look for- and clean all Grounds- look for bad Grounds on Motor, Chassis, CPU, Measure Alternator output Voltage, Battery Voltage, etc.
10) Look at your 02 Sensors, Remove, Clean- do not test on resistance with VOM as it can fry them! You can see them working on the Scantool, if one is not within range or pegged- Change it.
11) Check all your Vacuum lines, any questionable lines; replace. Check Injector Connections, Remove, Clean, reconnect.
Hopefully this will yield some results- if not directly, where to look.
The drive Cycle recording is VERY important. Note values and verify on paper ST & LT Fuel Trim, 02’s, Coolant Deg.,Timing Min/Max, F.P., Load% when Car is at the point it has the power loss. This is likely where you’ll find the issue, if the others did not yield results.
It’s important to do a Tune up and establish a baseline, along with the rest. It should cost little, Good Luck! Ill follow up with this, others may as well. John
