You really need to have AFR numbers at this point as they will tell us what's going on with fuel and AFR. We need to know if fuel mixture is causing this, if it's not mixture then it's ignition.
A really good decent permanent mount WBO2 gauge is the AEM gauges, decent price easy install. Something like this one:
Aem 30 4110 Digital Wideband Uego Controller Air Fuel Ratio Kit New Bosch 4 9LSU | eBay
To properly test the idle and WOT switches you just need a 12 volt test light or a volt meter. With test light you can test like this:
- With engine off and no key in the ignition
- Take the red lead from the test light and wire it to a fuse in the rear fuse panel, you just want 12 volts wired to the light's red lead.
- Pull back the rubber boots on both the WOT and Idle switch so that you can access the 2 pins for each switch from the back of the connectors. You want to leave the harness connected to the switches but be able to access the pins from the back side. To do this the rubber boots need to be pulled back off the harness.
- Now take the '-' lead from the light and touch both terminals at the back of the idle switch. If the idle switch is close and at idle both terminals MUST light the light.
- Now open the throttle so you come off idle, when you do this one of the 2 terminals will cause the light to go out. Meaning, one terminal always has the light lit no matter if the switch is open or closed (this is the ground side of the switch). The other terminal is the signal side of the switch and this terminal goes to the DME. This other terminal is the one that goes from light lit at idle to light not lit if you come off idle.
Then the WOT switch is similar in that it also has 1 terminal that's the ground terminal and will always have the light lit. The other terminal will light the light as the throttle reaches about 80% or more. With the WOT switch you are looking for the light to be out at less than 80% throttle and then the light comes on at more than 80%.
You can also test the switches with a ohm meter with them unplugged but that does not fully test the switches ground terminal nor does it test the switch in an active state. I always test them connected with my procedure above.
You can't clean the idle switch it's a sealed unit, if it's bad it needs replacing. The WOT switch can be opened up and then the contacts can be cleaned, often the WOT switch has corroded contacts since it sees little use.
Test both of the switches.