At a complete loss
 

I have a 2000 SL SOHC manual and I am plagued with issues that persists! If anyone has any idea what may be wrong or how to proceed effectively that would be much appreciated! 👌


Current issues are as follows:

* High idle, Especially with the first cold start of the morning.

After it warms up I can cut the car off and back on and immediately fix high idle until I press the gas again then it's back to 1500 Rpm or so.

* Sputtering, or slight pop during idle.

* Misfire or sputtering and loss of power while driving that gets worse with lower rpm or heavy acceleration ( The easier I am on the throttle the better it gets)

* Check engine light (EGR code )



I have tried the following to fix the issue:

✓ New brass engine coolant temp sensor and repaired to exposed wire to said sensor.

​​​​​ ✓ New Throttle Position sensor

✓ New EGR valve and an attempt to clean EGR tubes without taking them off the engine.

✓ tried the starter fluid trick to check for vacuum leaks

✓ New spark plugs with proper gap.


The issue started with high idle and worsened with the poor running condition a few weeks after idk if that helps or not. The car ran perfect when I got it and after a few months the issues started thoughts on what to check next?

Shotgunning parts is not a good way to find and fix an issue. Have you checked it for engine codes? That's the first thing you should have done. Retrieve the codes and post them here. Maybe we can give you some help then.

Please provide how many miles and any other known repairs. How much engine oil does it use?
thanks

256,000 miles on the odometer. So far I have replaced the egr valve with a new better quality one made by WVE which fixed the egr code. Found bad plug wires and rusty connection to the ignition coils to be the misfire issue. Runs great now with no codes. However I am getting the high idle intermittently still. More so when it's hot.. again I can immediately fix it by cutting the car off and back on. Sometimes it doesn't do it at all other time it high idles around 1500 to 2000rpm The the whole time. I removed the throttle body a f cleaned it to the best of my ability and that seemed to work for around 4 or 5 days. Anyone have a long term solution?

I believe Derf has posted before that the intake gasket between the manifold and the head is prone to leaking. This can cause idle issues.

Manufacturing oops on 3rd generation SOHC engines. Intake manifold gasket is not well enough supported between the intake for number one and number two. Part of the gasket gets sucked into the intake creating a vacuum leak as it is pulled out of position I have seen the throttle position sensor get messed up on these cars such that you can pull over, turn it off turn it right back on and the idle issue is gone until it comes back. You said you have replaced that so I would say that is not the issue. If cleaning the throttle body is something that buys you five days of peace, you may wish to check your idle air control valve on the throttle body as it may not be moving properly. Won't make a difference unless it is at idle. Whatever you do, to not make adjustments to the base idle of the vehicle with the base idle adjustment screw.