Hello, everyone. I have a 2001 Camaro, nothing fancy, mostly stock besides the exhaust and some cosmetic lovin. The problem is that I have been without the car for about 4 months now, and lack...err...proper funding to get it sent off to a dealerships mechanic to be diagnosed and fixed. I will if that what it ultimately comes to but I have some mechanic skills myself and would like to fix it myself. Symptoms: No acceleration or throttle response. Pitchy idling (smooth/normal to rough/choppy). Check Engine and Reduced Engine Power lights on. Diagnostics That We Have Already Tried: Changed the oil. Changed the battery and checked for low voltage. Purchased and installed a brand new throttle body. The head gasket had blown a month prior to this and we had redone it, and replaced all the gaskets between. The oil drained this morning was free of water and unusual residue. Besides the rough idle and acceleration problems, the car/ engine is in great running order, never had a problem beyond the blown head gasket and the current problem. When plugged into a pocket OBD2 Scanner I get two codes: P1518 and P1518 pd. Online research leads to a issue with the Throttle Actuator and the Powertrain Control Module or the 'intake stuck open'. But, I am unsure how to check any of these and I'd hate to blow a couple hundered on random parts due to poor diagnostic skills and still have the same problem. I am open to any suggestions. Thank you very much.

Also, I don't know if it may have anything to do with it but I had a Flowmaster muffler installed about a week before the problem rose its ugly head.

 

Welcome to the forum. Sorry to hear about your baby.
This is the introductions area and doesn't always get viewed that often by members. Your best bet for assistance is to post this in the 4th Gen section if you haven't already. Plenty of highly knowledgable ppl here that will be more then willing to help you out. Unfortunately I'm not one of them (the highly knowledgable mechanics wise), lol.

 

Well, I think you have more than one issue here. But let's talk about your throttle body first. Have you replaced your throttle body sensor? It may have gone bad. To test it, turn your car on. While your car runs, tap your throttle body sensor and if your car changes it's idle then it's a good chance the sensor has gone bad. Another way to test the sensor it to hook up a volt meter to it and see if the volts are steady at idle or not. You can do a visual check on it also. Take it off and if the wires are still silver then it should be good. If the wires are discolored, then you should replace it. There are good videos on this on YouTube.

Also, when did you change you plugs and spark plug wires?

 

Possible causes
- Dead or weak battery
- Poor circuit connection - Check Throttle Actuator Control (TAC) module connector for water
- Faulty Throttle Actuator Control (TAC) module Help with this


When is the code detected?
The Engine Control Module (ECM) has detected a loss of data or invalid data from the Throttle Actuator Control (TAC)
Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- No throttle response

P1518 CHEVROLET Description
The Throttle Actuator Control (TAC) module contains data which is essential for proper TAC operation. The TAC module continuously test the integrity of this data. When the TAC module is unable to write or read data to and from random access memory (RAM), or the TAC module is unable to correctly read data from the flash memory or and internal TAC module processor fault is detected and the Detected Trouble Code (DTC) is set.

I'd check the wiring to and the operation of the TAC.