It strikes me that this is a sensor issue rather than a misfire, but wanted to run it by others with more experience to make sure it makes sense.

04 6mt, 40k on reman, compression test within the last thousand miles.
I typically run at 77/78 on the highway, which puts me just under 4k rpm. Occasionally I get a flashing CEL without a noticeable stumble or change in note. If i drop down to 3k or shift it goes away. I cannot replicate it in any other gear, having tested 5th on the highway for 5-10 minutes at a time, and 3/4 on secondary roads when the urge strikes.

has anyone experienced a similar problem?
thanks

 

It's a misfire. Search.

 

A flashing CEL is pretty much always a misfire. When did you last replace your coils, wires, and plugs?

 

thanks for the replies.
I asked the question because I had not seen others with such a specific gear/rpm combination in the flashing cel threads. however I recently took it on a longer drive and got a flashing cel above 4500 rpm in third, so it seems to be garden variety misfire. I replaced the coils, wires and plugs last summer, so they have a couple of thousand miles. I will go through the suggestions in the other cel threads.
Got distracted from the problem with some recent snow, and I picked up an 89 saab 900 convertible yesterday, but it should be warm soon and I'll get it sorted in time to run some autox at pitt race.

 

I had stupid power loss at random RPMs that were intermittent. Sure enough it was the good ol ignition system to blame. Coils/plugs/wires. Make sure they are OEM at the very least for the coils.

 

My CEL is indicating misfire in 6th gear as well. Sometimes while accelerating, sometimes while cruising, sometimes while decelerating...sometimes not at all.

Usually it just lasts for a few seconds at a time then goes away, but once in a while the CEL stays lit after the flashing stops.

There is no noticeable change in performance.

For my ignition I'm running the IGN-1A setup from Sakebomb. It has never given me any problems.

I just tested all coils & plugs using the HEI tester for rotaries.

When I pull the DTCs I get:

P0301 "cyl. 1 misfire detected" (the culprit. "cyl.1" being rear rotor, I believe)

P0410 "secondary air injection sys." (air pump delete)

P0442 "evap. emission sys. (small) leak detected" (not sure...have found 0 vacuum leaks)

P2270 "O2 sensor signal biased/stuck lean" (cat delete)

Side note: I have the O2 sensor code and air injection code masked, but they're always there even if the CEL doesn't come on.

Have checked e-shaft sensor.

Compression tested - good

Fuel pump is good, only a couple years old, never run below 1/4 tank.

Premix - YES

Plugs were replaced prolly 5k mi ago. When I pulled them for the comp. test they seemed darker than brown -- almost black, but not "chunky".

Am going to go clean MAF sensor now.

Anything I'm missing? I'm open to all ideas/suggestions.

Thanks guys.

 

resetting the ESS profile (NVRAM) may fix the flashing misfire CEL issue

Resetting the ECU


anytime the ignition/timing system is altered this should be done, including the trigger wheel/main pulley, sensor, plugs, coils, plug wires, etc.

or the flashing misfire CEL too
.

 

Thanks Team. Up until reading your link I had just assumed that the NVRAM gets reset anytime I flash a new tune, but I'm happy to learn I was wrong.
Gonna try it tonight & see if it helps. (I have a good feeling about this!)
Will keep you posted.

 

UPDATE:

Yep... that dun done the trick!

Definitely the suggestion of the year in my book. If you were within a 100 mile radius of me I'd buy you a beer, or whatever your imbibitional beverage of choice may be.

Thanks again!