p0308 intermittent

[kobx02]

2015 5.7L 98k miles. Getting the p308 code, intermittently.

I've replaced all spark plugs (prior to this code), and swapped cylinder 8 with cylinder 7 to see if that changed anything. I first noticed this code when chasing the infamous P0441 and P0457 codes back in early May. After replacing the gas cap, the PCV, the vapor canister, and the EVAP leak detection pump, finally got the CEL to stay off. As of May 16th, everything was OK until last Friday (6/30) the truck shut off after I remote started it. Low and behold the CEL was on, and it threw the p0308 code again. I cleared the code, and so far so good.

Next step is to swap a coil and see if it "moves"....but with it being so intermittent, I'm scratching my head. So my questions to the experienced techs are:

1. What else should I try?
2. Should I start suspecting lifter failure and thinking about removing the head for inspection?

 

[Wild one]

Try the coil swap,you could also swap the injector from another cylinder,if it still throws the code,then #2 is probably in your future.If it turns out to be #2 throw a cam in it at the same time.

 

[Sherman Bird]

2015 5.7L 98k miles. Getting the p308 code, intermittently.

I've replaced all spark plugs (prior to this code), and swapped cylinder 8 with cylinder 7 to see if that changed anything. I first noticed this code when chasing the infamous P0441 and P0457 codes back in early May. After replacing the gas cap, the PCV, the vapor canister, and the EVAP leak detection pump, finally got the CEL to stay off. As of May 16th, everything was OK until last Friday (6/30) the truck shut off after I remote started it. Low and behold the CEL was on, and it threw the p0308 code again. I cleared the code, and so far so good.

Next step is to swap a coil and see if it "moves"....but with it being so intermittent, I'm scratching my head. So my questions to the experienced techs are:

1. What else should I try?
2. Should I start suspecting lifter failure and thinking about removing the head for inspection?

Where and what brand of plugs did you buy? As a seasoned and well experienced professional, I've seen and heard of counterfeit plugs EVERYWHERE, over the past 3 years or so. I'm currently using exclusively NGK plugs from O'Reilly and another local chain. It has stopped REPEATED misfire codes and comebacks which showed up (all of them) right after new plugs were installed... using motorcraft on Fords, AC Delcos on GM, and Champions on FCA vehicles.

 

[kobx02]

Where and what brand of plugs did you buy? As a seasoned and well experienced professional, I've seen and heard of counterfeit plugs EVERYWHERE, over the past 3 years or so. I'm currently using exclusively NGK plugs from O'Reilly and another local chain. It has stopped REPEATED misfire codes and comebacks which showed up (all of them) right after new plugs were installed... using motorcraft on Fords, AC Delcos on GM, and Champions on FCA vehicles.

I used NGK LZFR5CI11 plugs purchased from Amazon. All 16 came to $125

 

[Wild one]

I used NGK LZFR5CI11 plugs purchased from Amazon. All 16 came to $125

Sherman has a good point.Amazon and Ebay NGK's are famous for being Chinese knock-offs,especially at that price

 

[Sherman Bird]

I used NGK LZFR5CI11 plugs purchased from Amazon. All 16 came to $125

Amazon is a great place to buy water filters and many other things. Auto parts have really been targeted over the past decade in an especially hard way, for counterfeit. Trying to save by jumping over a dollar to pick up a dime is not really the place for those plugs. The people who deliver the packages to me have a nasty proclivity to throw them carelessly, instead of placing them in the event of the part's fragility. I recently bought 2 Toyota wide band air/fuel ratio sensors. (Oxygen sensors). These devices are VERY fragile akin to an incandescent light bulb. Both were broken/ defective right out of the box. Fortunately, the vendor made things right for me.

Those spark plugs are made of porcelain and they are very delicate as well. You also must torque them to exact specifications... not what "feels" right. Also, be mindful of keeping the socket straight/ square while installing the new new ones, lest you crack one.

 

[Burla]

It looks like he already swapped 7 with 8, so it's not plugs.

But how soon after you changed plugs did this happen. I think you might have a chance it is coil, maybe something happened during tune if it was recent to code. Swap coils

Does it ever run or idle rough?

 

[kobx02]

No, thats whats got me scratching my head a little. Performance wise and gas consumption wise I have seen or felt any differences. Truck runs like a champ. I'm hoping its not the lifters since it seems to be so random and inconsistent. I honestly thought I had it fixed when I swapped out the PCV.

By the way, since this code popped last Friday, I've been driving the truck around, including highway speeds and there hasn't been any issues (fingers crossed).

 

[JHoward]

No, thats whats got me scratching my head a little. Performance wise and gas consumption wise I have seen or felt any differences. Truck runs like a champ. I'm hoping its not the lifters since it seems to be so random and inconsistent. I honestly thought I had it fixed when I swapped out the PCV.

By the way, since this code popped last Friday, I've been driving the truck around, including highway speeds and there hasn't been any issues (fingers crossed).

Maybe you bought a set of "chinese garbage made plugs" as a couple of folks mentioned?

What do you have to lose in purchasing a known brand from the rip off dealership to see if that solves your issue ... maybe, that's not a guarantee, either?

 

[kobx02]

I don't disagree with that being a possible scenario, except the fact that I switched the plugs with Cylinder 7, to see if the problem moved....and it did not. If it was the plug, I would expect the p307 code to pop, but it stayed at p308.

 

[kobx02]

Is there a way I can listen to the engine with a stethoscope or something, to see if I can hear a ticking coming from that cylinder? For context, my manifold bolts are shot so it does tick because of that....I want to figure out a way to determine if my lifters are also ticking. Reason being, I want to repair it all in one shot if thats truly the case.

Thank you all for the replies/help so far.....

 

[Wild one]

Is there a way I can listen to the engine with a stethoscope or something, to see if I can hear a ticking coming from that cylinder? For context, my manifold bolts are shot so it does tick because of that....I want to figure out a way to determine if my lifters are also ticking. Reason being, I want to repair it all in one shot if thats truly the case.

Thank you all for the replies/help so far.....

Start with a compression test,quite often a bad cam lobe will show up with a compression test.If that cylinder is down compared to others,then you can pull the valve covers and check that cylinders rocker movement,if the rockers aren't moving as much as the other rockers,then you know for sure it's time for a cam/lifter replacement.

 

[RGC440]

If you're running 87 octane, upgrade to 89. Clear the codes and try again.
I had the same issue with my Challenger, this cured the proble.

 

[SouthernBornRebel]

could be Fuel Pressure Sensor line...... easy replacement

 

[t0ymach1n3]

PM me and I can hook ya up with a full run down on the P0308 DTC and exactly what to check. I'd start with any of the things on the below list, that you might not have looked at to track down the cause of this rather than chasing your tail

FUEL DELIVERY SYSTEM​

IGNITION COIL, WIRING, OR CONNECTORS

ECT SENSOR, WIRING, OR CONNECTORS​

MAP SENSOR, WIRING, OR CONNECTORS​

O2 SENSOR, WIRING, OR CONNECTORS

ENGINE MECHANICAL SYSTEM​

POWERTRAIN CONTROL MODULE (PCM)​

 

[Sherman Bird]

I used NGK LZFR5CI11 plugs purchased from Amazon. All 16 came to $125

I am currently unraveling multiple problems on a 2008 4Runner v-8 with a chronic P0174/ P2197 codes and 60% total fuel trim on bank 2. This guy has been messing around with this problem for 2 years and the list of parts (Parts cannon fodder) is extensive. When queried about WHERE he got his "factory, Toyota" parts, he stated Amazon as well as other online places. In my exhaustive diagnosis, I found among many other disturbing problems, a bad, low quality POS fuel pump which he swears he bought from an online source of "Genuine Toyota" parts. The oscilloscope waveform confirmed it as a counterfeit piece of garbage. Just replacing the fuel pump with a good high quality brand straightened up 16% of that extreme fuel correction. That's huge!

Your "NGK" purchase from Amazon might warrant more scrutiny. Those plugs could be fake, but you'd need an oscilloscope and training to cull that out.

 

[kobx02]

PM me and I can hook ya up with a full run down on the P0308 DTC and exactly what to check. I'd start with any of the things on the below list, that you might not have looked at to track down the cause of this rather than chasing your tail

​

FUEL DELIVERY SYSTEM​

IGNITION COIL, WIRING, OR CONNECTORS

ECT SENSOR, WIRING, OR CONNECTORS​

MAP SENSOR, WIRING, OR CONNECTORS​

O2 SENSOR, WIRING, OR CONNECTORS

ENGINE MECHANICAL SYSTEM​

POWERTRAIN CONTROL MODULE (PCM)​

I appreciate the offer.

So far since the start of this thread, the CEL has not come on (hopefully I didn't jinx myself). I just ordered all the stuff to fix my manifold studs (resurfacing existing manifolds, new OEM gaskets, and studs) and will be tackling that job next week. This way that tick will be eliminated and I can start listening for the lifters.

 

[Sherman Bird]

I appreciate the offer.

So far since the start of this thread, the CEL has not come on (hopefully I didn't jinx myself). I just ordered all the stuff to fix my manifold studs (resurfacing existing manifolds, new OEM gaskets, and studs) and will be tackling that job next week. This way that tick will be eliminated and I can start listening for the lifters.

I will preface this with "I don't know"!!! I have cured MANY of the old HT4100 Cadillac engines with the broken bolt/ exhaust leak issues. I did it by ELIMINATING the gaskets, having the manifolds surface finished ala a cylinder head surface (very smooth), thoroughly cleaning the head exhaust surface, and painting the exhaust manifold surfaces with extreme high temp paint and assembling the manifold while the paint was still wet/ tacky, torque the NEW bolts to spec, and leaving the thing to let the paint "CURE" for a couple of days. NOT one of these ever had another exhaust leak. Just a thought... but I do not know if this has been tried on the HEMI.

 

[Jwithing]

I had the same problem with cylinder 7 and 3 for years. I replaced everything mentioned here and only thing I didn't do was the compression test. I checked the rocker arms and all looked good. What finally did it for me was 3 rounds back to back of Red Line SI-1. Gas mileage came back after thst too. Maybe I just got lucky, but may be worth a shot. Currently have 120k miles and had 80 to 85k miles when it started.

 

[Prestonguillory14]

Is there a way I can listen to the engine with a stethoscope or something, to see if I can hear a ticking coming from that cylinder? For context, my manifold bolts are shot so it does tick because of that....I want to figure out a way to determine if my lifters are also ticking. Reason being, I want to repair it all in one shot if thats truly the case.

Thank you all for the replies/help so far....

I’m gonna say that it is probably a lifter but maybe a lil change might help it a little bit