I'm trying to figure out a coldstart misfire with my wife's '03 TLS. I want to check the coilpacks, but have not found anything in the forum that tells me what/how to check for.

Anyone have any ideas on how to check if a coilpack is bad?

TIA

 

if its runing normal when warmed up, im not sure there is any way to test them. usually you check for an impedince or voltage if you suspect that its bad all the time.
Have you had the car pluged in to see which cylinder/s are causing the missfire?

 

the best thing to do would be to replace all your spark plugs (most likely the problem) if you are having a misfire problem - that would at least narrow it down a lot if the car still does it.

 

If you suspect that its the coil pack then unplug each coil HARNESS one at a time, if theres no changes to the engine idle(the one you just pull out) then thats the bad coil. Makes sense?

 

If you unplug a coilpack when the car is running for sure there'll be a misfire. I'm gonna see if I can lookup the info via Mitchell or something.

 

But since you said how can you test or identified that the coil is bad or not, that is an easy way of checking. For example , say your #5 cylinder is misfiring and your pulling out the others, So you pull out #1 coil and seem that the engine idle will drop or hesitate, then that one is working fine. Then you continue to the next coil, unplugging and reconnecting back on each one at a time.

Then you come across #5 and when you disconnect it, the idle is still the same(misfiring), WHY? because thats the bad one. It will misfire even with its plugged in or not.

Or like the the other said, test the resistance with the multimeter.

 

The problem is that it only misfires when it's coldstarted in the morning. And it only misfires for a little bit, so there is only a limited amount of time to do "testing."

I was talking to someone else about this today. It's true that the OBD2 should store misfires in the computer. But also, after x-amount of time of "normal" status, the obd2 will clear out the misfires. So I actually borrowed a computer and will hook it up to the car in the AM and see if any codes come up right away. Otherwise it's almost next to impossible to figure out.