Misfire on all cylinders

Hi everyone I recently purchased a Tundra at a Car auction. I thought I made out like a bandit with the truck. Only to have it misfire on all cylinders. I’ve changed spark plugs, coils. Fuel injectors Pcv valve also the air check valve. And soldered the air pumps since they were not connected when I checked. Just finished changing a valve gasket today. Have any of experienced this before ? Any help welcomed thanks

 

Which engine?

Done a compression test yet?

 

It has the 5.7l have not done a compression test or leak down test. Prob should have started there. I know. But I am hoping it’s not anything major which is looking to be so.

 

Check for air leaks. I had an an air leak after the maf and caused random misfires. So you have p0300 and p0301-p0308? To have all cylinders misfire you have a bad maf or airleak I could see 1 or 2 cylinders low compression but not all. I'd suspect an air leak, low fuel pressure, clogged fuel filter on pump. Use some maf spray at all hoses intake runners etc.

 

I will definitely check all that out. Thank you. I did do a Compression test all cylinders seem to be good within 10 psi of eachother. I was leaning towards bad valve seals since the spark plugs get fresh oil on them.

 

Are you talking about the plug tips or the valve cover spark ug seals have oil on them?

 

Good news on the compression test.

As MDL asked, when you say fresh oil on the spark plugs, are we talking on the electrodes, or externally on the insulator / in the spark plug tubes from leaking seals in the valve cover? I’m thinking you mean on the electrodes if you’re suspecting valve seals…


If that’s the case, and all plugs are oily, I’d be having a very good look at what is in the fuel tank. Filled with diesel before being sent to the auction? Or other oil dumped in as vandalism? Or ???

 

Vvti issues? but odd for both sides. Oil on the plug seals could possibly work down but all cylinders? Good compression on all, 189psi with no more than 10-15psi variation.

 

I did change out the driver side valve cover gasket and plug hole gaskets. But it didn’t change anything. I get oil on the spark plug threads. I haven’t found any leaks and I tested the maf sensor seems to be working. Stored codes are misfires on cylinder 2, 3. And all others pending. But will most likely they will be in the coming days like always .

 

Other problems I guess I sorted out with this truck was the one of the air pumps one was disconnected. From a bad crimp job so I solder them tested them the work fine. Replaced the air check valve a code for it came up. The gasket were very bad placed on it. I’ll post pictures. I put new gaskets aswell. I thought this would fix my issue. Previously found an exhaust leak I fixed with job weld high heat will weld it soon. Changed injectors , fuel regulator , Pcv valve. From what I gather from a VIN check I did this truck was parked for many years possibly 5 then 3 after. I wish I would have taken pictures the first time I saw the intake valves. There was a lot of oil I couldn’t even see valves in some cylinders.

 

These were the spark plugs it had. And honestly do not seem old at all. They are dry here but when taken out there was fresh oil on them also very lose in my opinion. I changed these out and put new denso spark plugs. And they are beginning to look like this too only the top half though. And those are barely a month old.

 

Are those plugs supposed to be iridium and where did you buy them. I only ask because if they are supposed to be iridium’s, the little iridium disc that weld to the ground lug do not look like they are there. You have to be very careful on who you buy parts from, since places like Amazon will sell counterfeits that look exactly like the real thing. The counterfeits will start giving you problems right at start up. Hope you get your problem resolved very soon.
Also, ALWAYS double check your gaps before installing them. Most the time they are correct, but I’ve run I to a few that were way off.

 

@Danny3737 Thank you Danny. I Believe they are. But I installed the densos iridium with the oem gap. Those as well had oil residue. But not as bad. I’m thinking it’s because they have not been in there so long. But even for a month that is bad. I cleaned them off as best I could and put them back in. Honestly thinking it’s gonna be a blown head gasket. Kinda see a leak on driver side. Looks pretty clean might be coolant. Got a suspension oil and coolant mixing coolant does not look Toyota pink. More like orange. Will prob do a block test today. And maybe even pressurize the radiator see if I see it leaking. Misfires at cold start. And seems like it too much condensation with a lil white smoke. Also looked like the truck had a lot of coolant when I got it and not so much any more. I marked the coolant level at operating temp. Will mark it cold. Might see the difference when I turn it on today. Was hoping that was not the case. I’m starting to prepare myself.

 

@Danny3737 might need all gaskets. Did a dollar vin check. This truck possibly got auction off in 2017 Too. Smh and possibly parked for 5 years driven some. Then parked for another 3. Haha laugh so I don’t cry. lol I can’t afford a truck payment right now. So I can’t give up on this truck.

 

Think she is worth saving. Plus it’s my first truck.

 

Did a block test it passed. also pressurized the coolant system. Did not drop psi. Waiting on adaptors to do a fuel pressure test. I keep looking for leaks I do not find any . Will do a leak down test shortly too. If needed.

 

Following. Curious to see the results of the leak down test.

 

A couple other things to consider is a worn pcv valve and valve cover/spark plug tube gaskets

 

@Orions Dad I changed the Pcv valve and valve cover gasket on the driver side along with the spark plug tube gaskets. Problem still persist unfortunately.

 

Any luck on figuring out the misfire?

 

@KKev87 not yet.this weekend I’ll prob do a leak down test.

 

Following.. 2012 Platinum 228k miles. Had my truck for 8 years, I've put the last 120k on it. Same issue for the past 6 months, cold start - all 8 cyl Misfire, warms up then runs fine. Have replaced: coils, plugs, injectors, valve cover gasket, plug seals, Cat bank 1. My mechanic is stumped too.

 

OP hasn’t posted back in a year. The mystery may never be solved….