Seeking Beginner DTC Advice, 1995 E420, No ASR

[luckymike]

UPDATE:

Have done some driving with the new Bosch caps and rotors. Car runs smoothly except for idle, when it will stumble periodically at a stop light. It's a pretty big stumble at times, like someone turned the key off and back on.

Not ready to ask for help yet unless someone knows this exact symptom. I plan to pull codes soon to see if anything is amiss.

Will also disconnect the MAF again and also spray some carb or brake cleaner around the base of the ETA to see if I messed up somehow when installing.

Stay tuned but don't hold your breath. Third car and unregistered due to failed smog so not getting its typical use.

 

[luckymike]

UPDATE:

Spent some time at a friend's shop this morning to work on the miss. Started by looking for vacuum leaks. He had this cool handheld tester that somehow sniffs them out. Nothing.

While fiddling around, the car seemed to start stumbling less. My mechanic friend suggested I give the smog test a try so I did. Got the car good and hot and he took me right in. It passed! HCs were high and just under limit at 92 out of 100 allowed. Whew.

But I have a two-year reprieve now during which I can slowly chip away at the miss problem. It isn't always there. I don't think it's noticeable when cold but will continue to check that. When warm, it is sometimes barely there and other times quite pronounced, like the key was turned off and back on.

Without any basis for this opinion, I just have a feeling it may be ignition related. New coils but who knows. And I've messed around with the plug wires enough between changing plugs and caps and rotors that I wouldn't be surprised if one or more had a problem. My buddy has a Sun scope and I hope to get the car checked out by him soon.

In the mean time the car is back in service and we'll see if miles and time make any difference.

Oh, smog guy said he's been having good luck running two cans of Sea Foam in a half tank on the freeway to clean up the cats. He has noticed multiple times that the computer monitors go green while monitoring during this treatment. I don't see any downside and will likely do this just before the next test in two years.

 

[gsxr]

If you can get live data (from SDS or MT2500) for the EZL, you can watch ignition voltages displayed. Misfires will appear as voltage spikes, confirming the "miss" is ignition. IIRC, @Trae had a similar problem on one of his cars which turned out to be a faulty injector...?

 

[dionphaneuf]

Hey @luckymike did you get this solved? I've had this very similar issue and think it was caps and rotors...the 'Uncle Buck' style random backfires are pretty embarrassing, especially at startup. I've got new ignition coils I need to install....

 

[luckymike]

@dionphaneuf I apologize for this late reply. I have not been watching the forum.

Car is running PERFECTLY. I don't know why this thread didn't get updated. Though the ETA did need to be replaced, the answer to the stumble was plug wires. I'm pretty sure I wrote about this somewhere...

 

[cascade]

I apologize for this late reply. I have not been watching the forum.

You've been over on Benzworld, which is your real home. No need to apologize, because that's a good thing.