I am totally lost on what is going on. First let me describe whats going on.

A few days ago we were driving and the engine light came on and started flashing. I took it to NAPA to run the codes;
P0306 = Misfire Cylinder 6
P1300 = Random emission misfire
P0300 = Random/Multiple misfire
P0304 = Misfire Cylinder 4
P1590 = ABS? Three Amigos, i have them just haven't fixed yet.
P1668 = Alarm?

Based off of that I went and got new plugs, wires and coils and had a local mechanic to replace.

Then he stated I still had codes firing but they were different.
P0300 = Random/Multiple misfire
P1590 = ABS? Three Amigos, i have them just haven't fixed yet.
P0302 = Misfire Cylinder 2
P0308 = Misfire Cylinder 8

From that I took it home and replaced the Mass Airflow Sensor myself. and now i have a new one that just popped up.
P1300 = ???
and the same 0302 and 0308.

It runs with very little power and acceleration. I am beyond frustrated, we have had this for a couple of years and this is the first real problem we have had. Any ideas or help?

 

What light came on? year? engine?
just comparing what you have here it looks like you have/had random misfires on 2, 4, 6 & 8 now they are on different coils, so you can rule coils out of the picture. You say you have replaced the plus and wires so i guess you can rule them out, unless they are cheap wire or someone dropped a plug. But 2, 4, 6 & 8 are on the same head which is more concerning.

 

After what has been done, and considering the cylinders are all on the same side, my mind goes to head gasket and a clogged catalytic converter.


Have you been losing coolant?

 

It is a 2001 Disco 2 SE. V8 4 cylinder engine. The Service Engine Soon light came on and is flashing when you push on the gas.

 

How involved is the head gasket and the catalytic converter?

 

Well I had terrible problems just like that and went on a mad parts replacement binge, finally resolving it, but never fully understanding what had gone wrong.


I can tell you I replaced the following:


MAF
Plugs
Wires
Head gaskets and all associated gaskets/rings
catalytic converters (whole Y pipe)... but it was working okay before I did that.


I may have replaced other things, but if so I don't recall.


What I think is odd about your issue is that all of those cylinders are on the same side, and they are all of the cylinders on that side. So it is something that affects them equally. Can't be the coils (they cross sides), you have replaced the MAF (wise decision) and the wires and plugs. I am sure you paid close attention to the wires going to the right place on the coils. since the head gaskets are divided by side, my mind goes to that, but you have not mentioned losing coolant. If you are losing coolant, then I strongly suspect your head gaskets. If not, I strongly suspect your catalytic converter. However, there would need to be a reason for one side cat to clog up, too, and that is generally gas or coolant being flushed into the exhaust. When mine failed It sounded like a ticking or rattling after it warmed up. Have you heard anything like that?


Maybe flailing a little here. I am not an expert, but I have had similar problems. Maybe some real experts will chime in.

 

Sounds like the you have a mechanic, so maybe this isn't something you would try, but you could drop the exhaust from the manifold and start her up, paying attention to any wires or flammables that might be in the way of hot exhaust, run to the driver's seat, and goose it a little. If the engine revs then the cat is a problem. If not, then it is something else. Your neighbors will hate you. Just six nuts to remove from the flanges.


Needless to say, that needs to be a pretty short test, lest the lack of backpressure cause burnt valves or worse.

 

We almost ran out of gas the other week and we had to put in a low quality gas. We put half a tank in. I didn't think anything of it until after the check engine light came on. We then filled it up with a high octane and an octane booster. It seems like all of these problems started after I put the gas in. We also do have a slight coolant leak. We keep an eye on it and add coolant when it gets low.

 

You would need to consistently be running low octane gas in it to see any issue. I run 87 in mine once in a while with no negative result. Higher octane is better though.
All this aside, I don't think thats your problem. If it is your cats wouldn't you have codes relating to that? I didn't see anything relating to cats or O2 sensors in your code list.

 

Thank you much for your help. going to take a look at the CAT and see if I can fix it.