I own a 1986 190e, 8 valve gas. It starts easy and runs smooth until it warms up. After it gets warm the idle begins swinging from about 300 rpms to 1000 rpms. It is still running smooth at this point, its just that the idle is swinging up and down. Can anyone give me some probable causes and tests to confirm the cause? Any help will be appreciated.

Welcome Benzomatic-

There are lot of threads regarding this issue. Try using key words in the search feature. Try: idle 190e erratic

Here is one: 85 190e 8V hesitation

Haasman

__________________
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)

There are a lot of threads but many of them go off on tangents and never really address the issue. Also, my description differs from many in that the car starts and runs well except that the idle searches only after it is warm. Also, none of the threads I read seemed to give methodical trouble shooting schemes. At any rate, I would like some real gurus to respond, or at least some one who can say, "Test part A and if ok then test part B. To test part A do this..." I know it is asking a lot but I really like the chalenge of the trouble shooting w/ out just replacing parts. I also realize that sometimes replacing a part is the only recourse for trouble shooting but I know that by-and-large I should be able to take a methodical approach and get to the core with out a lot of hunting and pecking. Again, I know my expectations are high but people here seem willing to help out, even if its been discussed before. So I am asking everyone out there to give me a hand and help me enjoy my toy!

As a side note, I have done this to the car myself:
- Remove the head and replace the valves, guides and seals
- Had valves ground and head resurfaced - at the machine shop
- Replace the timing chain and cam gear
- Rebuilt the sunroof mechanism and replaced the cable
- Repainted the car
- Replaced the blower motor

And the list goes on. I only mention this to let folks know that I am willing to dive in with their advice and give it a whirl.