Engine Misfire? Not Transmission Issue :/

[RetroJohnny]

Hello everyone! So as few of you may know I made a post months ago about a possible transmission fault, hard shifts and what not. I finally brought the Reatta into a transmission shop fully prepared to shell out $1000 for a complete rebuild.. Aaaannd the mechanic test drove it for many miles, took me along too and said the transmission is actually in great shape for being 180k+ tranny, he could not find anything wrong with the transmission during diagnostic (it had too much fluid in it though, probualy my wrong doing) and he saw no reason for a rebuild, sigh of relief! BUT, I was dumbfounded when he said that "slip" I was feeling was not the transmission, it was the engine having a misfire. I thought it was the transmission all along slipping hard, silly me, but it is so random and out of nowhere. It is the worst in between 30MPH and 55MPH, and will "hiccup" two or three times in a row, but trans is in lock -up during said hiccups so it really can't be the trans. But I need someone's help on where to go next? The sparkplugs are about a year old, new ICM, new ignition coils. The only thing left ignition wise are sparkplug wires.. Could my issue be that simple.. new wires? FYI.. Everytime that engine misfires the CRT lights up in the "Service Engine Soon" warning.. every time! I check the codes and the only one that sticks out ignition wise is E041, cam magnet right? I hear that part is a booger to replace, I have the part I just don't think I'm up for that big of a job. So if anyone out there has some direction for me I would greatly appreciate it, Thank you!!!

[2seater]

Cam sensor shouldn't cause a misfire, but it is possible you have a bad plug wire. What other codes show up? There are unrelated items that might also cause a misfire or something that feels like it. A misfire will be most obvious when at low rpm as the transaxle goes into lockup, many times in the 45-50ish mph range. If using the Magnavox style ignition, you might consider closing up the plug gap a bit to around .045-.050" if nothing else shows up.

[RetroJohnny]

1 hour ago, 2seater said:

Cam sensor shouldn't cause a misfire, but it is possible you have a bad plug wire. What other codes show up? There are unrelated items that might also cause a misfire or something that feels like it. A misfire will be most obvious when at low rpm as the transaxle goes into lockup, many times in the 45-50ish mph range. If using the Magnavox style ignition, you might consider closing up the plug gap a bit to around .045-.050" if nothing else shows up.

Hey 2seater, there are other codes they are as follows. B482, B446, B447 and C553. I know two of them have to do with A/C components. And that you for the tip on the plug gap, I would have never thought of that. When tune-up time comes I will for sure close it up a little more. Could it be the ignition coil by any chance? I know the Magnavox coil is unreliable but it is only a year old, so hopefully not.

[Ronnie]

9 hours ago, RetroJohnny said:

The only thing left ignition wise are sparkplug wires.. Could my issue be that simple.. new wires?

In my experience the spark plug wires are the most likely thing that would cause the misfire you are having at low RPM  when the torque converter is locked and you try to accelerate.

[DAVES89]

Plug wire is a quick and easy fix. Maybe do the oxygen sensor while you are there.  

[Ronnie]

1 hour ago, DAVES89 said:

Plug wire is a quick and easy fix. Maybe do the oxygen sensor while you are there.  

Good advice. I consider the O2 sensor to be a maintenance/tuneup item just like spark plugs and wires.

[2seater]

10 hours ago, RetroJohnny said:

Hey 2seater, there are other codes they are as follows. B482, B446, B447 and C553. I know two of them have to do with A/C components. And that you for the tip on the plug gap, I would have never thought of that. When tune-up time comes I will for sure close it up a little more. Could it be the ignition coil by any chance? I know the Magnavox coil is unreliable but it is only a year old, so hopefully not.

I don't think any of those codes will cause your issues as you originally surmised. As others have suggested, new plug wires are a good idea especially if their history is unknown. The Magnavox ignition gets a bad rap that I feel is undeserved, although the later Delco is demonstrably more powerful. The Magnavox ICM does appear to have a greater failure rate than the Delco, but conversely, the Magnavox coils appear to have less issues than the Delco. I believe the failure of one half of the package, coil or ICM, long term will cause the failure of the other half. I would do the plug wires first and investigate further if the problem persists.