doom239

Hi guys.
So for the past 3-4 months I have been getting these random misfires with my car
So I started changing parts on it to see if I can get it fixed, First I changed the plugs, Now a couple of sensors. But yet the Problem is still here.
What happens is I cannot press on the gas pedal hard at all. as soon as I do the car goes into limp mode from the misfires.
Here are all the codes that come up. hopefully someone can chime in with some help.


P0304- Cylinder 4 Misfire Detected
P0305- Cylinder 5 Misfire Detected
P0303- Cylinder 3 Misfire Detected
P0302- Cylinder 2 Misfire Detected
P0301- Cylinder 1 Misfire Detected
P0300- Random Multiple Cylinder misfire Detected
P0108- Manifold Absolute Pressure/Barometric pressure Circuit High Input

lizardjack

Upstream cats collapsed and plugged downstream ones.
Check the back pressure in the exhaust.

doom239

Do you really think its my Cats??

02C32guy

I can't speak to the misfires, but I can tell you that a clogged cat can put the car into limp mode. One of mine is partly clogged and under WOT the car will go into limp mode. Doesn't affect me any other time though.

doom239

Humm ok I will go under and check the cats.
If your right Should I just get my Primary's deleted and just stay with my secondaries?
or just replace them with high flow ones?

lizardjack

I've cut all 4 and had the ECU reprogrammed so that the downstream O2 sensors would not send the feedback.

MASTERBENZ

Have you replaced your Spark Plug Wires?

doom239

Yes I changed them with the plugs to the magnacord 8.5mm ones

MASTERBENZ

Does it do at idle, under load, snap throttle, all time??

doom239

Yes it ides perfectly fine its only when I press the gas pedal about 1/4th to 1/2 of the way.
I get this mad shaking and misfires

c32jet

Did you ever figure it out? I am having similar issues.

Thanks

Gramma_Benz

Those of you that have early model C32's and have missfires, make sure you check out your camshafts. They are press fit on and the cam lobes have a tendency to move.

this happened to me and luckily instead of blowing up my engine, I blew a head gasket.

Hopefully it's not your cause, but just throwing it out there. Good Luck!