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Discussion Starter #1
I am now the proud owner of a 93 Hardbody but unfortunately am having problems with the emissions test I need to do here in Ontario. The engine is the 4 cylinder 2.4L. It has not been driven much in the last 4 years and was parked every winter. This means there is very little rust, but that's not helping me right now.

Here are the numbers from my smog test - car was nice and hot:

HC ppm : Idle 57, Limit 200 - Pass 40 km/h 72, Limit 64 - FAIL
CO%: Idle 0.01, Limit 1 - Pass 40 km/h 0.22, Limit 0.35 - Pass
NO ppm: Idle NA 40 km/h 134, Limit 929 - Pass

Things I've done:
- Changed Oil
- New Spark Plugs (old ones have some carbon deposits)
- Ran seafoam through vacuum (brake booster)
- tested plug wires - resistance is good
- looked at distributer cap - looks pretty good inside
- can't see any vacuum leaks
- no ECU error codes

I noticed usually Hydrocarbons go down at higher rpms. Why would mine be going up?

Also, my engine idles fairly high (around 1500 rpms when hot, closer to 1000 rpms when cold)

It seems to drive smooth with good power. It's new so I don't have anything to compare it to.

Please help!
 

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Discussion Starter #3
It has about 250 000 km's. Cat was replaced only 5000 km's ago.

I'm wondering if it could be the TPS or MFS. Any ideas?
 

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Discussion Starter #6
can't set idle and running lean

So my Idle Air Control was disconnected. I re connected it and now it is idling better but I still failed the e-test. I've read that when your mixture is too lean Everything is extremely low except you Hydrocarbons, thus I think my mixture is too lean.

When I disconnect my TPS the truck idles at 2000+rpms. I tried tightening the idle adjustment screw but it is as tight as it will go. Do you think the IAC or AAV could be the problem? Can I clean them out?

Any help would be greatly appreciated.
 
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