My first thought would be that the timing chain is not installed correctly. It is very hard to get the marks lined up correctly.
All engine sesnors. ie TPS, MAP, O2 sensors, EGR, etc.......
There are four oxygen sensors on a 2002 Intrepid. There is one before, and one after the catalytic converter on each side of the engine.
There are four total oxygen sensors. One before and one after the catalytic converter on each side of the engine.
try replacing the thermostat
Then you may want to have a mechanic check it out.
No
Reset it with an OBD2 scan tool. If it came on after replacing the sensors you may have another problem. Reset it and see if it comes back on.
The O2 sensor is in the down tube just in front of the transmission on the drivers side. I have changed it from the top, Trust me, it's worth jacking the car up and replacing from below.
If replacing with a different size engine ie. 3.3 to a 3.5 you should use the computer for that engine, and if it is the same engine 3.3 to a 3.3 it is not necessary.
I had all sensors replaced in my 03 Trailblazer and the check engine light stiil comes on. Why?
You can not reset your oxygen sensors. You can only replace them. To reset the check engine light you will have to get that done by a repair shop with a computor. If replacing the sensors does not repair the problem then check for a vacuum leak.
The chain usually lasts the life of the engine. It only needs changed if it has failed.