Flashing CEL, New Cat. Conv., EGR, Denso Iridium Plugs

[IrmoSCRodeo]

Here’s my story…I’ve searched this forum and can’t find this exact problem.

About 2 months ago, my 2001 Rodeo (LS V6 3.2L, 90k) started the now infamous rough idle / idle fluctuation between ~200 RPM and 2000 RPM / stalling and the CEL came on (steady). The first round of diagnostics revealed a bad catalytic converter on the left bank…had that replaced ($ouch$). Problem not solved.

The next round of diagnostic checks revealed something about the EGR valve and either restricted flow or excessive flow (can’t remember now). Had that replaced as the shop said it was too far gone for just cleaning (I know, I know…they just took me for my money…I now know that a good cleaning would probably have done the trick…lesson learned). Problem solved…sort of.

In addition to all of the other codes during the previous diagnostic checks, the P0300 (random misfire) code was present. After the EGR replacement, the Rodeo purrs like a kitten, however, I now have a flashing CEL during acceleration.

I decided to change the plugs myself, pretty simple DIY job. I used the Denso Iridium plugs ($13/ea)…why?...because I did not do my homework to determine that the platinum plugs ($6/ea) were suffice. Still a flashing CEL during acceleration.

Took it to Auto Zone to have the codes checked…no code stored. They could not reset it (let’s just say “operator error”). Anyway, I did the ol’ unplug-the-battery trick and then started her up.

NO CEL!!! Well, until about a mile down the road…then it started flashing during acceleration.

I’m looking for your thoughts? Could it be the spark plugs, although I used Densos? Or are you thinking Intake Manifold Gasket?

[amigo-2k]

Odd that there is no codes ....

I think intake manifold is the logical next step ....

How old is the battery?

[IrmoSCRodeo]

battery is 6 months old...

everything I read here says that a flashing CEL is very bad...but the things runs great...

[rodeo02]

You dont hear of a bad IMG to causing a misfire, but it is entirely possible if the vac leak is large enough. I'd bet you have a bad IMG accompanied by the wrong spark plugs. IMG r/r is covered by the 10/120 warranty if that applies to you.

G/luck
Joel

[marcre]

I let my IMG go for a bit before replacement. I was getting misfire codes before I got it replaced.

[amigo-2k]

When I had my IMG the dealer said they were getting misfire codes, yet I had no CEL. They of just been nice, knowing it is a common problem and just swaped it out for me....

[IrmoSCRodeo]

UPDATE...

When to Advance Auto last night after work...the CEL was solid and then flashed when I accelerated. They checked codes...P0300 (Random/multiple misfire). She cleared it out and said to see if it came back...

Yup...1 mile down the road.

It is NOT misfiring...I would feel that. It accelerated perfectly, without hesitation, and runs great. It's either the IMG or this thing is VERY peculiar about it's spark plugs (because i put iridiums instead of platinums...dumb move).

I plan to check the IMG this weekend with the ol' carb cleaner (O2 safe) around the manifold intake to see if that exposes a leak...that's a $3 test for me. If that doesn;t expose the problem...looks like I will spend another $40 on the platinum plugs and see where that gets me.

I will update on Monday. In the meantime, feel free to offer any more advice.

I love this truck...I want to run it forever, but it is close to getting about 4 rounds of buckshot in the manifold!!!

[rodeo02]

If seen posts where owners had the flashing CEL / misfire, but could not feel any performance issues. It was due to wrong sparkplugs. (applies to 2000+ ONLY!!)
G/luck
Joel

[dropsnout]

The 2000+ 3.2 need to have only the denso plugs that Isuzu calls for,or you will have misfire or check engine light problems. The flashing checke engine light while accelerating can be cleared by taking the negative cable off the battery and touching it to the positive cable for at least 30 seconds. Put the correct plugs in it and clear the capacitors in the PCM and you should be okay.

[weathermedic]

I have an '01 Rodeo V6 with 52k on it. I had the flashing CEL come on only under acceleration a few weeks ago, with no problem that I could feel or detect.
I had my IMG replaced, EGR replaced, cleaned my PCV valve, changed my throttle and pedal position sensors in the months prior to this (CEL never flashed before these things were replaced) I ordered the Denso spark plugs from sparkplugs.com for $6 and change each, thinking this was the problem. After I let the truck sit overnight, the flashing CEL hasn't come back on. I have not changed the plugs yet (scheduled to have the mechanic at my job do it in 2 weeks)
Can't really figure out why it happened, but with 52k on the truck, it is time to change the plugs anyway.

Jason in NYC

[IrmoSCRodeo]

Originally Posted by dropsnout

The 2000+ 3.2 need to have only the denso plugs that Isuzu calls for,or you will have misfire or check engine light problems. The flashing checke engine light while accelerating can be cleared by taking the negative cable off the battery and touching it to the positive cable for at least 30 seconds. Put the correct plugs in it and clear the capacitors in the PCM and you should be okay.

...clearing the capacitors in the PCM...is this a seperate function aside from disconnecting the battery?

[dropsnout]

clearing the capacitors in the PCM is done by touching the negative cable to the positive for 30 sec.

[2eyefishclaw]

your problem is the ION module it is located under the hood and is hidden by the work of the plastic briggade remove the plastic cover from the top of the engine twoards the back of the iintake you will see a module with three connectors going to it this is the ION module if you replace it your problem will go away. not a doubt in my mind

[IrmoSCRodeo]

Final Update (I hope)...

I ordered new spark plugs from Sparkplugs.com and they came in yesterday. I had put in the Denso Iridium plugs just last week (read previous posts), but still had the CEL problem. Well, I pulled those out last night, put in the Denso Platinum plugs and unplugged the battery for the duration of the job (to clear the codes...the whole touching the cables together for 20 seconds doesn't work...at least not for my 2001).

NO CEL!!! Drove it a few miles last night...no CEL. Drove it in to work this morning (about a 15 mile commute with interstate driving)...no CEL.

The moral of this story?... Rodeo's (2000+) are VERY peculiar about the type of plugs that go in them. For these years, be sure and use the Denso Platinum (K16PR-P11)...and nothing else.

As an aside, kudos to Auto Zone. I called and spoke with the store manager about this. Since the iridiums were listed in their computer as the original part (platinums aren't even listed as replacement), and that ended up being my problem, he is going to refund my money. For now, Auto Zone has a customer for life.

[rodeo02]

Originally Posted by IrmoSCRodeo

...As an aside, kudos to Auto Zone. I called and spoke with the store manager about this. Since the iridiums were listed in their computer as the original part (platinums aren't even listed as replacement), and that ended up being my problem, he is going to refund my money. For now, Auto Zone has a customer for life.

Wow! That is REALLY good! I'm surprized your AZ even dealt with denso's in the first place. My closest AZ gave me a blank stare when I asked for NGK plugs! I do use AZ exclusively for my oil, lubes, sprays, airfilters, wiper blades, etc.. Simply because they are good about reading OBDII codes and taking used motor oil. Good to hear the
K16PR-P11's did the trick. It's brutal these are the only plugs we know so far that work!

G/luck
Joel