1988 ciera 2.8 154000 miles.
Car started to idle rough, not to bad seemed sporadic. I changed plugs. No change in idle. It did have more spunk. Took car to Auto Zone and they hooked there Diag. to it. Error MSG were 21, 13, 23, 33, 34, 54,61,63. Changed the O2 Sensor and the TPS. In order to get to the TPS I had to remove a sensor, I think? It is sitting on top of the TPS and plugs in to the throttle body also has 4 wires to it. I took this unit off Two screws only and it has a spring and a small shaft. I forget what they called it. (low idle adjuster or?) That unit looked pretty beat up. Black inside and seemed loose. I probably screwed it up. Anyway . when i got it back in I reset the computer, unplugged the neg term for 30 seconds. and started the car. It runs very rough at idle, or coasting at any speed or on deaccelerating. When I give it gas runs excellent and very strong. Got back to hook up diag. again. Error msr. was 14. They said something w/ O2 sensor, Unplugged or something else is effecting it. I think it has something to do with the unit that Sits above the TPs/ Please help. Thank you