misfires not missed

my dads tundra is a 2010 limited with the 5.7l. he bought it used at 67,000. for 2 years now no one has been able to fix its problem. it misfires every time you start it. if you start the engine and immediately put it in to gear and start rolling the truck will run fine until you stop at a light or idle for more than 5 seconds. once it idles it will set a code and run on the remaining cylinders. not always the same cylinders. Toyota's fix is to replace the engine, but who has that kind of money laying around. anyone know what could be the problem? no other codes have came up just P030X. good harness, good plugs, good coils. any help with this nightmare would be helpful. thank you.

 

Clean your MAF sensor, check your purge valve and have your fuel pressure checked to see if it's marginal or good. Those are some of the things I would do.

 

Cleaned MAF but don’t have a way to check fuel pressure. I did notice that all the misfires are on the even bank. Could it be a leak in the VVT seals from the cams to cover? And did you mean EVAP purge valve?

 

Rent fuel pressure tester from Autozone, Advance, Oreallys, etc. You'll have to put a deposit down but will get it back when you return it. It's free otherwise..

 

I would inspect for rodent damage as well, especially if the misfires are all on one bank.

A new engine won't solve the issue.

Where are you located? There may be shops close to you that people could refer you to if we knew where you were.

 

Intake/vacuum leaks will cause random misfire. So it only happens on bank 2 (driver side)? Bank 2 misfires would be P0302, p0304, p0306, p0308 - do these all show up at the same time or randomly. Could have an upper or lower intake leak on driver side. Bad MAF would not only show up on one bank, it would affect both sides. Not sure about cam tower leak, but unless you have leaking valves I don't think the cam tower leak would cause a missfire. So no other codes, could be electrical.

By any chance were the spark plugs inspected on drivers side?

 

Will try to get fuel tested. No other codes. No harness damage. So far I get p0300, p0308, and p0304. Have not looked for vacuum leaks yet.

 

Found yesterday that #8 & #4 holes are severely low on compression. We will be rebuilding our engine. Thank you all for your help and ideas.