So, after some brickboard research and troubleshooting, I have my plan of attack to get my 1990 volvo 240 to pass the emissions test (fails all three at 40 km test NOT idle) and run smoothly for a few years (hopefully).

Here it is:

1. Replace Intake Manifold Gasket and Engine Coolant Sensor (original)

2. Clean AMM and Throttle Body with appropriate CRC cleaners. Replace TB Gasket.

3. Replace Idle Air Control (orginal) and Fuel Pressure Regulator (7 years)

4. Replace Cap and Rotor and 3 piece Flame Trap Kit (2 - 3 years)

5. New Catalytic Converter and Header pipe. (Cat failed, Header Pipe has a leak)

6. Oil Change.

7. Emissions Test

My 240 fails the emissions test in all three categories each time (EVERY TWO YEARS)and only passes when I install a new CAT... So, my car is basically a CAT killer.

I was planning on doing everything myself except the Cat and Header Pipe (I've ordered both pipes already, so just labour) and I might consider having my mechanic do the intake manifold gasket and engine coolant sensor depending on his price and the time that I have.

I was also planning to do the repairs/maintenance in this order. Does anyone have any feedback on this plan? Would it make sense to do it in a different order? Any parts you would consider adding or things to check while doing these repairs? I understand I might not necessarily need to do all of this, but I was also trying to be a bit preventative...