2000 Passport P0300 code problems.

I aquired a 2000 Passport a week ago. I knew the converters were bad, so I replaced them along with all four O2 sensors (Bocsh). It was still riding rough sometimes and the CEL blinked when I pressed the accelerator pedal, so I got the codes read and P0300 came up. After spending about 2 hours on this website, I decided to check the plugs. They were autolites, so I replaced them with NGK. It was still not running right, so I replaced the IMG's (not really that difficult to do). It seems to be idling better, but the CEL still blinks when I accelerate, and I do not think my engine has the power it should have.

I think my next step is to check for coil placement (how do you know which one goes where), or the ICM ($700). Any further help would be great.

I would try re-seating the the plugs on the coil packs.

Have you cleaned out the the EGR? EGR tube? Throttle body?

i think you are going in the right direction with the coil packs due to the flashing CEL (mis-fire).

-Ryan

I don't see how a p0300 code (random cylinder misfire) could be bad coils. It's highly unlikely they could all be bad. I would be checking the low voltage wiring to each coil pack and then checking the grounds and battery cable connections. Do you know how to do a voltage drop test?

Yes, I cleaned the throttle body and EGR valve and I checked all the ground wires. Explain a voltage drop test. I may have done it before, but just not familiar with the term. Would this be for my coils or alternator?

I made sure all of my coil packs were seated properly. The next thing I did was to let my engine idle until it started missing again. I disconnected the connectors to the coil packs one by one. Each one on the passenger side made virtually no difference, but the one's on the driver's side almost stalled the engine. It seems as though I'm running on three cylinders sometimes.

Do you hear any intake leaks?

I cannot here an obvious leak, and I've sprayed carb cleaner around all of the attach points and gasket surfaces and no change in RPMs. Plus, I just installed a new IMG set, so I doubt that I have an intake leak. If I did have an intake leak, wouldn't my problem be constant and not sparatic?

I may have induced a couple of my problems. I have read that I should use Denso plugs (p/n K16PR-P11), but I used NGK-R laser platinum. I asked the parts guy for Denso, but he assured me that the NGK-R's were the same or better than the Denso's. Should I put Denso's in? Then when I replaced my IMGs, I may have over torqued them, but I cannot find a leak right now.

If you have the old plugs yet, reinstall them and reset the battery and see what happens.

The plugs I pulled out were Autolite platimuns, completely wrong. So I will have to purchase the Denso's and hold onto my $12 per NGK-R's. I write back when I have the Denso's installed.

Now I'm getting a little frustrated. Does the exact Denso P/N PK16PR11 have to go in this engine. I ordered Denso plugs, but I got the Iridium Denso P/N IK16, and this Passport still runs like crap. Do I need to get the original P/N plugs for this engine to run right and not give a blinking CEL everytime I press the accelerator? Just trying to figure out if I'm chasing a ghost with these spark plugs and my problem is something else. :banghead:

OK, my problem got worse, so it should be easier to find. Right??
I drove the truck for about 60 miles with the iridium Denso plugs. The truck started running very rough about 4 miles from my house. I barely made it home. I pulled the plugs and the right bank plugs were completely fuel fouled. The left side looked like they were burning OK. Then I got the Denso Double Platinum, which is what it is supposed to have. The truck started but still runs very rough. Through pulling connectors from my coil pack, I have found out that I have completely lost my left bank cylinders. Is there a chance that I screwed up my new converters by running it with the P0300 code for 2 weeks?
Through searching the forum it seems it could be a MAF, Cam position sensor, crank position sensor, low fuel pressure, throttle position sensor, ion sensing module, etc. I took the timing belt covers off and it looks like my timing belt is in good condition and my timing marks are lined up.

well i reread your original post, and it seems from reading that, that you are not so much worse as back where you were. is this right?

and i wouldn't go kicking yourself about screwing something up, it's more that the correct diagnosis hasn't been made yet. it's puzzling.

none of the possibilities you mention compute because none of them are specific to one set of cylinders, including the cats and 02 sensors. any problem with any of these components would affect the whole system not just part of it.

these engines and computer systems are excellent at masking problems by adjusting fuel,air,timing etc to compensate for problems. your isolating the problem to one bank should be helpful, if you are sure of that info. did you disconnect the IAC before you disconnected the plug coils for your rpm test?

if the problem is one side, then i would start looking at wiring harness, and at fuel delivery.

btw, did you do a compression test? that would at least rule out a head gasket problem.

and did you make certain you had the coils installed to the correct cylinders ? !

//bc

I would try pulling on the wire harness while it is running. maybe there is a break in one of the wires?