I have an '96 360 Magnum that's stalling occasionally, getting some really bad gas mileage (running very rich), and is idling quite rough, the revs also bounce sometimes between 600-1000rpm when in park.

Plugs have been changed and looks quite clean, here are the codes I'm getting (in order):

P0108 - Manifold Absolute Pressure/Barometric Pressure Sensor Circuit High Voltage
P0133 - O2 Sensor Circuit Slow Response Bank 1 Sensor 1

After a lot of reading I am thinking that it is probably my MAP sensor that needs replacing but I really don't know, anyone got any thoughts/advice for me?

 

ALSO forgot to mention, I am not sure if this is a different problem or if it is part of the main problem but I am also getting a P0351 - Ingition Coil 'A' Primary Control Circuit/Open.

 

If it runs..... the P0351 code is just a fluke. Clear codes, see if it comes back.

Check your plenum. If it hasn't been fixed yet, it is more than likely blown. That leads to failed O2 sensors (which you have) and clogged cats. A fair few of your symptoms point in that direction.

 

I have considered the plenum but after a lot of monitoring I can report that it's not using a lot of oil, in fact it doesn't use oil at all and I'm not getting any pinging either. I'm pretty confident it isn't the plenum but I intend to do the magnet test if I get opportunity this weekend.

 

Honestly the magnet test isn't gonna do you any good. All that proves is the plate is steel or not. Doesn't say anything about the possibility of a blown plenum either way...

Need to pull the throttle body and check or signs of oil pooling.

 

Ok, thanks for the advice, I'll give it a go and check back when I know more!

 

Basics first, do a comp test before you go any farther.

Just do the job, don't bother looking for oil in the intake. Once done you'll have peace of mind that it is not leaking.

 

Ok, thanks, look like I'm going to have a busy weekend! I am hoping it's nothing serious as the bottom was only rebuilt 15k ago (big end was on its way out). It has only done 83k now! Needless to say the previous owner has done a lot of work in the past (which is why I am hoping that all of the obvious stuff such as the plenum has already been done).

I'll give everything the once over and report back when I know more. Thanks for the advice.

 

Just another quick question if you guys don't mind....

The previous owner has put K&N rocker cover breather filters on in place of the standard part. They are due for replacing but first I want to know if there is any advantage to the breather filters or if the standard part is better, from what I have read there's arguments for both sides.

 

So no pcv system? I prefer the stock system over the breathers.