Misfire issues perhaps more?? (2 Viewers)

[Gonefly470]

Hi all. After searching here for similar stories mine seems a but unique and decided to ask. Here my issue.

2001 lx470 180,200 miles.
Spark, plugs, timing belt, coil, valve cover gaskets, pullies, water pump, thermostat, new radiator, drive belts, fuel filter, steering rack and a whole host of other items done exactly 2 years ago but only driven about 1k miles since then. Sitting in garage, no rodent problems, full tank. On battery tender wver few months to top it off.

FF to today, I have been wanting to replace the heater tees. Since the truck had been sitting for so long, I decided to do them. Repalced without to much issue expect for when pulling out driver side tee it seems the end of one was missing. Just the lip portion. Unsure if this broke when I was moving the clamp or it had been like this for a whole since the break had coolant residue on it and didn't seem to fresh. But if it was. Those pieces fell into the metal hose coming out of the engine. Couldn't retrieve any pieces. No issues on the passenger side one.

Once completed I started it up. Smooth at first then a little rough. Check engine flashing with vsc lights on. Once I verified no coolant was coming from repalced hoses, I turned it off and check my obd2. P0301 code. Misfire fire cylinder 1. I did a quick visual and couldn't seen anything out of the ordinary. Vehicle had been sitting undisturbed.

I figure it has to do with it sitting for so long, do after code was cleared. I turn it on again and proceed to drive around my neighborhood. No light but do notice some hesitation at first. Then blinking light again. I continue to drive and light turned off for a good while. Then back on. This happens for about 7 seven miles as i looped back home.

Arriving back home the hesitation started getting more pronounced and shaking at red light. I limped it home.

Arriving home I Check the ob2. Now codes. P0303, p0304 and p0300. No p0301 anymore. I check everything under the hood. No smells or leaks, cleared the codes again and drove it about .8 mile around the block.
Rough running and hesitation continues. Now code p0303 and p0300 persist. Vsc lights turned on again.

Long story I know but I have never had any issues after the major service in 2023. Ran great. Could this have been caused by debris from the heater tees? I'm doubtful? Low battery? Anything else??

 

[AARONTLC]

One thing you mentioned is that it has sat for a long time. Old stale gas possibly? I would think that the debris left inside by the heater tee's would cause overheating issues not rough idle. You also said no rodents but 18mos is a long time. Might want to just verify there isn't a nest or at least leavings under the intake or back up against the driver side corner firewall. Clean the MAF, check air filter box. Battery truly is strong? Maybe get a free battery test done just to rule it out? Good luck!

 

[Gonefly470]

One thing you mentioned is that it has sat for a long time. Old stale gas possibly? I would think that the debris left inside by the heater tee's would cause overheating issues not rough idle. You also said no rodents but 18mos is a long time. Might want to just verify there isn't a nest or at least leavings under the intake or back up against the driver side corner firewall. Clean the MAF, check air filter box. Battery truly is strong? Maybe get a free battery test done just to rule it out? Good luck!

Definitely no rodents. It's my active garage.

I filled it up about 4-5 months ago. So perhaps. But I use shell premium strictly.

Battery was purchased new in 23 as well, exactly 2 years ago. Definitely hasn't been on a tender the whole time. Just every few moths. Charging it now. I did install a new alternator when all the work was done. All parts were oem.
If the battery is weak and I top it off and clear the codes should that solve it? Or once weak, it needs to be reaplced?

 

[Gonefly470]

After poking around I opened the air filter housing and a strong smell of fuel came out. Unsure of what this means

 

[leveeguy]

After poking around I opened the air filter housing and a strong smell of fuel came out. Unsure of what this means

Possibly a fuel injector issue.

 

[Gonefly470]

Perhaps. Could the vehicle sitting for months cause a blocked injector?

What i find interesting is that at first, it read cylinder 1 misfire. After driving a while the flashing CEL turned off then on shortly after and I now have been getting a cylinder 3 misfire, random multiple cylinder misfire and now strictly cylinder 3 again.

Could the blockage clear after driving a bit since it has been sitting for some time?

Possibly a fuel injector issue.

 

[Gonefly470]

Could my replacement of the heater tees have caused this?

 

[leveeguy]

Could my replacement of the heater tees have caused this?

Na cant see that being possible. Vehicle not being driven more likely reason. Changing fuel filter would be good start for possible fuel injection issues

Edit: I see you changed fuel filter previously. Maybe if you can clear code or disconnect battery for 20-30 minutes then try another restart and let idle, to see if it may smooth out. Add some fuel treatment to gas to help with the process. How many miles driven since TB change? Is throttle body clean?

 

[Gonefly470]

Na cant see that being possible. Vehicle not being driven more likely reason. Changing fuel filter would be good start for possible fuel injection issues

Edit: I see you changed fuel filter previously. Maybe if you can clear code or disconnect battery for 20-30 minutes then try another restart and let idle, to see if it may smooth out. Add some fuel treatment to gas to help with the process. How many miles driven since TB change? Is throttle body clean?

Here is the work that's has been done to it in the last 2 years. Current mileage 180,633.

I did think about adding fuel treatment. Probably will do that and let it idle.

Already cleared code multiple times and disconnected battery. Battery currently on trickle charge for top off.

Just opened cleaned TB and inspected MAF sensor. All clean. That's when I noticed the fuel smell in the filter area.

Last time it was turned on before today was the oil change in January.

 

[Gonefly470]

 

[Gonefly470]

Could any damage result from letting it idle for a while?

 

[leveeguy]

Could any damage result from letting it idle for a while?

I’d say idle 5-10 minutes if no lights on dash then take a spin. If fuel smell persists in air box, leaky fuel injector should be the issue.

Edit: check your work area near tees wire connectors, vacuum lines etc to be sure no loose or damaged connections

 

[TahoeZ]

Sounds like bad gas/fuel delivery. A few months is a long time for these modern fuel blends. Even though you topped the tank a few months ago, you still have gas older than that in the tank when you did so, and gas that was older than that the tank before. If it's going to sit for a while, ethanol-free with Stabil Marine is best.

I would siphon some fuel or disconnect the line at the filter and run some into a clean can. Even a brand-new filter can quickly be overcome running bad gas through it. After that, I agree with above; injectors are the most likely culprit. They start having issues when sitting for too long.

 

[Gonefly470]

I checked the area around the tees. All looks normal. I did get done coolant spillage when changing them but I don't think that would have gotten into the wiring or harnesses? They seem well covered. Plus most of the coolant ended up on thr ground.

The area looks normal to me. No obvious hose or wiring issues.

I did add some techron FI cleaner and started it up this morning and the smell of fuel was heavy at startup. Dissipated a minute after.

Cleared the code, but it pops back up immediately. It is only thr p0303 code. No more p0301 or p0300. I even had a p0304 briefly when driving it yesterday.

Since plugs and coils are new I doubt it could be them especially since I initially got a p0301 code and havnt since.

Here are some pictures of the engine area and behind the tees if you guys spot anything out of the ordinary. Thanks.

 

[Gonefly470]

 

[Kamran Khan]

Those ignition coils doesn't look OEM to me. Heater T has nothing to do with misfire.

 

[Gonefly470]

Those ignition coils doesn't look OEM to me. Heater T has nothing to do with misfire.

What are you noticing that makes you say that?

 

[Gonefly470]

I swapped out the coils. 3 to 1 and 1 to 3. Still getting the p0303 code immediately after startup.

 

[Kamran Khan]

I swapped out the coils. 3 to 1 and 1 to 3. Still getting the p0303 code immediately after startup.

Did you clear the code after swapping the coil or you start the car without clearing the code

? Picture of the coil in my car just for reference.

 

[Gonefly470]

Did you clear the code after swapping the coil or you start the car without clearing the codeView attachment 3882629? Picture of the coil in my car just for reference.

From my research the ones with the stickers are direct from denso. But after looking into it it may be that I was duped. They were off a "legit" ebay seller.

I disconnected the battery for 30 mins. Swapped the coils. Reconnected,

started the car and cleared previous codes. P0303 popped up immediately after.