So it looks like there might be an overlay on my dash. Is the check engine light behind it? Because I don’t see any cel in the gauge lights.
The Check Engine Light is actually a Service Engine Soon Light. It is in the bottom right side of the Speedometer. My camera sucks so you cannot read it but it is the orange light under the odometer.
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If your '87 still has the TBI system your problem is simple and re-routing the exhaust exit will not fix the problem.
The O2 sensor is giving your ECU bad information because you now have "true duals". If you have defeated the smog system that only adds to the issue. Your truck is running too rich. This seems to be worse at idle speeds, at least it was with mine. Your computer was designed to run with a choked up single exhaust, catalytic convertor and air pumping into the manifolds. If any part of that has changed the system is not going to function properly.
I fixed this problem by contacting Harris TBI in Virginia and getting a Stage 1 chip. Before I did this my exhaust gas would burn my eyes and my throat any time I was idling. Fuel mileage seemed to be okay but at idle it was awfully rich. After installing the chip a lot of things improved with how the truck runs. This is a simple and relatively cheap fix. I can answer any questions you have about getting to the ECU and replacing the chip. Brian Harris can tell you what you need to do to make it run better.
