Misfire with flashing cel and no misfire codes.

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B

Bikepro

10 Year
Joined
Mar 19, 2011
Threads
4
Messages
23
Location
Dresser, WI
I'm at a dead end here with my truck and I'm hoping you guys can help. I've searched this site, my FSM, and almost the entire internet and cannot find any info on this. I have a bad misfire, a flashing cel, and no misfire codes whatsoever. The truck is behaving exactly as if it has a bad coil pack but I have none of the 300 codes. Instead, what I have are a bunch of EGR codes. I've owned this truck for four years and have put 130,000 miles on it, and have replaced probably 6-8 coil packs. Every time the coil pack gives itself up as a p030x code pointing at the bad coil pack, and sometimes I get The P0300 random cylinder misfire code.
Here's some history on what's going on now:
For the past week or so, I've had a recurring catalyst code (p0425 Catalyst temp sensor bank one) which I've cleared a couple of times. It has been taking two or three days for that to come back. My original thought is that I have a bad O2 sensor or something simple, but with what's happening now I'm wondering if all of this is connected. Over the same period of time, the truck has been acting as if a coil pack is going out. The truck will misfire for five or 10 seconds and then it will go back to running like normal. Unlike all previous coil packs, I have no misfire codes. Also unlike all previous coil packs this misfire is intermittent, where in the past they've always just died.
This is where it gets weirder. Yesterday morning I started the truck (cold) and it was misfiring, and the CEL was flashing. I shut the engine off, plugged in my scan tool, and I got a bunch of EGR codes along with the catalyst code that I've been getting lately. I wrote down the codes, cleared them, started the truck and instantly got the same codes again in this order:
P0425 Catalyst Temperature Sensor (Bank1)
P0400 Exhaust Gas Recirculation Flow Malfunction
P0403 Exhaust Gas Recirculation Circuit Malfunction
P0404 Exhaust Gas Recirculation Circuit Range/Performance
P0406 Exhaust Gas Recirculation Sensor A Circuit High

My gut is telling me to start switching out coil packs, as it's running like it has a bad coil pack, but this does not make sense logically. Also, as I understand it, these trucks do not have an EGR system, so the EGR codes are throwing me off completely. So before I start switching out coil packs..has anybody else experienced this or can anyone point me in a different direction? :bang:
 
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I'm really surprised and kinda worried that I haven't gotten any takers on this. Since my original post, I've swapped all of the coil packs around with a new one, and that is not my issue. Still misfiring, still EGR codes. Does anyone have a clue as to which system would give me EGR codes if these trucks don't have an EGR system? I'm failing to find anything.. Until now, I've had great luck on this site with even some of my harder tech issues, but I'm thinking I may have to look elsewhere on this one- do any of you have any resources that you'd care to share? Yotatech? others? I'm about ready to pay money
 
its recirculating exhaust gases when its not supposed to. fix the erg leak.

don't pay attention to me. I thought i was in the 80s section. lol
 
It's 4:45 AM and I've been trying to google this for 15 minutes now. Here are a couple of thoughts just to keep your juices flowing:

1. I found an instance in my searching where the ECU was to blame for EGR codes on a non-EGR equipped engine. This would be annoying and expensive to fix, so take that with a grain of salt.

2. Possible throttle plate/MAF mass air flow) sensor gunked up. Have you ever cleaned or inspected? I clean mine frequently. Three to four times a year.

3. Have you changed spark plugs in addition to coil packs? I've had my truck run like this and in one case it was a bad coil pack. But in the next case 6 months later, it was a bad spark plug. All new plugs solved that issue.

4. Final thought, one guy on a tundra forum with the 4.7 was getting similar behavior and it ended up being his fuel pump.

If it were my truck, the diagnosis/repair/replace procedure would go in this order:

Purchase MAF sensor cleaner spray and throttle plate/body cleaner spray and then disconnect the negative cable on the battery, then remove the air intake plastic and clean up that throttle plate and spray your MAF sensor with the MAF spray. Leave the battery disconnected for at least 30 minutes.

If problem still exists:
Replace spark plugs with recommended iridium replacements (don't skimp on these)

If problem still exists:
Replace all coil packs (you can get an entire set quite cheap on the Internet for testing purposes)

If problem still exists:
Look at fuel pump/take it into dealer.
 
Hey thanks a bunch for your time! I sure hope it's not an ecm issue.. I replaced my plugs with new iridium plugs about 30000 miles ago when I did my timing belt service, so that's not likely to be the issue, but I guess I can't rule that out either. I clean my throttle plate pretty regularly but it has been about six months on that so I will do that again so I can rule that out.
This morning, I switched out all of my coil packs and I thought I had it licked. It started up and ran and drove great for about 10 minutes, until the misfire appeared again, along with the flashing check engine light. I scanned it, and had all of the same EGR codes again, with the addition of two new EGR codes: P0404 and P0405. After clearing the codes again and restarting the vehicle, it is currently running normally, but only temporarily I'm sure. Man this thing is killing me!
 
could be anything in the fuel and ignition loop. We all jump to coil pack because it's the most common, but even the 030X codes are just "misfire" codes than can be plug, coil, injector, etc. I changed plugs and battled a stumble misfire for MONTHS. Finally threw in the towel and took it to the dealer. Diagnosis was "loose" spark plugs. Must've been, since it's never came back, a long time later. May, or may, not be related to your problem. Just "one more thing" to check off the diagnostic list.

https://forum.ih8mud.com/threads/in...fire-on-2000-lc-no-codes.592303/#post-8713523
 
Post back your results please. It helps future mudders
 
I don't know if you have worked on this any further, but with that p0425, you should rent a temp gun and an exhaust backpressure tool. You can install the backpressure tool to see if there is excessive backpressure from a clogged cat. The temp gun is an alternative that can verify the cat is clogged by the inlet temp being high.
 
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