lexusflex

I have been having some problems with my 96 SC400 acting very sluggish in low rpms. Between 1K and 3K, it won't go hardly at all. I posted a thread about it yesterday. My check engine light started flashing today, so I took it and had it hooked up to the computer. It said it was showing 11 codes. OUCH!!! Most of them were from the o2 sensors. The other ones are what are puzzling me. It had random misfires, but only on the odd side. Cylinders 1,3, and 5. The wires are good. The distributer cap and button are good. The coil pack on that side is good. Has anyone ever had problems with their Ignition Control Modules?? I am kinda wondering if that is the problem. Has anyone experienced this on their SC400 before??

O. L. T.

iTrader: (17)

all that can be MAF related since it all starts right there telling the engine what to do. Low rpm bogging is also MAF related in many instances. These aren't chevy 350's. "Fuel and fire" doesn't get them going. Start with common issues and throw some amount of reason out the window.

lexusflex

I have already replaced the MAF sensor. Done that in Sept. It went out on me, so it had to be replaced. Any other Ideas?? Is anybody out there that has had these problems, and it be associated with the Ignition Control Module. We have two of them on the SC400's one control the odd side and one controls the even side. This is what make me believe that one of them could be faul. Anybody??????

5sp_jzz30

iTrader: (2)

might be the igniters. there are 2 of them.

lexusflex

I have already replaced the coil on the odd side of the motor. This is what made me think that it was the ICM that was bad. Keep in mind that it is only misfiring on cylinders 1,3, and 5, randomly. Any other Ideas? Anyone? PLEASE!

SHOLEXMAN

SO before we start saying all of these possible things did you change the 02 sensors at all or no? IF not replace them if you haven't already. Clear the codes and see if you have the same issue. Sometimes one faulty part makes 6 other things kick in at once. Replace the 2 pre o2 sensors and you should have a noticable difference. If you have codes for the rear replace those also. Usually the post 02's don't go bad cause they don't have to deal with all the unburned fuel and other garbage after the cat.

lexusflex

Yes I reset the codes, twice. Still reading the same codes. I haven't replaced the O2 sensors yet, because I figured that the reason they were showing a code was because of the unburnt fuel being dumped on them because of the random misfire. I also thought that it was very rare that all four O2 sensors go bad at the same time. Normally just one at a time go bad. So, I was trying to fix the random misfire first. Then if the O2's are still showing codes I was going to replace them. I am fixing to reset the codes again and switch the ICM's around. If it starts misfiring on the opisite side then I know that the ICM is bad. This is begining to become such a pain in the ***! Any other Ideas?? Anyone??

SHOLEXMAN

It shouldn't be a pain in the *** cause this is what typically happens if something goes bad. Switch the ignitors around and see if you have the misfire on the opposite cylinders. There is a test to see if those go bad. I would have to look for it. If the check engine light is flashing it is a type A misfire either a coil,ignitor,or possibly a cap issue. If the switch doesn't help at all change the 2 02 sensors. It has happened for those to go bad at the same time funny as it sounds. If the Ignitor was bad it would be 4 cylinders instead of 3. I say replace the 02's. We will see young skywalker.......

lexusflex

It isn't really a pain in the ***, I am just a little aggravated about it. I did the switch drove it around for a while until the service light come back on. It didn't flash, it just come on. I have to go back to my friends house in the morning to hook it back up to the diagnostic computer to see what codes it is giving. Could the O2 sensors be causing the misfires? I do know that they can cause a lose of horse power. The point that you made about the ignitor causing four to misfire not three is what I thought at first, but thought that it was possible to have happened. I guess it is like it was said by O.L.T., start with common issues and move from there. I guess I will just have to keep eliminating possibilities until I figure it out. I will make sure to post my progress. Everybody feel free to add ideas or comments along the way. This is how we learn!

SHOLEXMAN

See what the codes are and it should be the 02 sensors replace them if the code comes up.

CleanCL

I've never seen an o2 sensor code when it wasn't the o2 sensor. Replace them.

It sounds like you had previous problems (bad MAF and coil pack) which would have run the car rich until you fixed those problems. Thus extra fuel was being used and probably burning up the o2 sensors. They finally have gone bad.