Car suddenly starts running rough and has no power

[Trav]

If you have an exposed exhaust manifold take an IR thermometer and aim it at the exhaust manifold flange of each cyl close to the head right after cold start, if one is cooler than the others that's the one you need to look at.

This works best on steel and tube style manifolds but if there is a little separation it also works fine on iron. I would guess secondary ignition issues that may possibly have now overheated and damaged the cat.
Meaning if you find the root cause was not cat related a new cat may be in your future anyway.

 

[wtd]

Thanks for the additional suggestions. I will use the IR thermometer on the exhaust manifold to see what that shows and than use the spark checker to see if I'm getting spark to the plugs.

As bad as it was running, it is a good possibility a coil took a dump since one coil runs two cylinders.

Wayne

 

[meep]

Due to popping I was going to suggest a cracked valve or other hotspot in the CC causing preignition/detonation or leaking uncombusted gas into the exhaust.

-M

 

[Rand]

How old are the plug wires?
Does this model have a known troublesome ignition module/coil packs?
sounds like a spark or fuel problem.

I might throw wires and coil pack(s) at it if they are inexpensive.

just to rule that out so you can focus more on other possible causes.

Can always return them if you need to.

 

[joel95ex]

remember the basics-----air, fuel, spark. i would look into the ignition coil/coils first as you didnt report any HG problems----a bad coil will make it run like complete sh-- and many people dont realize how bad it can run just from that..... also in the dark check for arcing wires ---will be a faint blue light like static electricity

 

[mk378]

Unplug the low voltage wires on one coil, if you have lost a coil and running on two cylinders this will either make no difference (you unplugged the bad one) or stop it completely (you unplugged the good one). You can then switch the coils to see if the problem really is a coil or if it is some other part of the system.

 

[wtd]

Well here is an update. This morning I started the car up and it idled normally for a few minutes and then did the idle drop thing and started running very rough. I tried using the IR thermometer on the exhaust manifold but the temps were all over the place and wouldn't stay constant so I then hooked my spark tester up.

Cylinder 1 and 4 did not have any spark and they share a coil. While pulling the plug wires, I ended up pulling the end out of the cylinder 3 plug wire so now I needed wires. Both of these had lifetime warranties and I keep all receipts so I knew I was good there.

I pull the one coil and discover it has a small crack in it so I'm pretty confident that I've found the problem. I go get the new parts and install them.

Start the car and it idles fine for a few minutes and then it starts missing again. cylinder 1 and 4 don't have spark again. Now I'm thinking it's the ignition control module. I take it off and take it up to O'reilly's and had them test it and their tester is acting up. They finally get it to start working and the module tests bad but the guy is still not sure if it's the module or their tester. He finally agrees to warranty the ICM which also has a lifetime warranty. They don't have it in stock so it should be here tomorrow morning.

So, do you guys think that the ICM is the problem? This one has around 95,000 miles on it. I don't know if the cracked coil caused a problem with the ICM. If I remember correctly, if one of these components goes bad, it can sometimes take out the others.

 

[mk378]

Yes one coil not firing would almost certainly be either the coil or the module. Also, working normally then suddenly quitting is something that bad modules do.

 

[wtd]

Originally Posted By: mk378
Yes one coil not firing would almost certainly be either the coil or the module. Also, working normally then suddenly quitting is something that bad modules do.


Thanks, I'm hoping this is what the problem is. The last time the module went bad, the car wouldn't even start.

Wayne

 

[wtd]

I replaced the ICM today and that seems to have fixed the issue. I let it idle for awhile and then took it for a drive and it continued to run fine. I kind of hate using the other old coil with the new ICM and one new coil but the coils are not very cheap and I had no reason to warranty it. Hopefully it all stays good for a long while. Thanks for everyone's help. I appreciate it.

Wayne

 

[meep]

Nice job there!

-m

 

[HoosierJeeper]

Good job! Fingers crossed.

 

[wtd]

Thanks guys. I've driven the car about 90 miles so far and it's still running so I guess that was the problem.

Wayne

 

[Piston_slap]

I had a very similar occurrence on a 87 2.0 Cavalier. Turns out that 1 of the 2 coil packs failed and it was running on 2 cylinders. Didn't sound like it was missing either.