11 Sierra P219a causes

[Little lady mechanic]

I have had my truck for about a year now and ever since I bought it its been throwing this code I need help narrowing down the causes. usually the check engine will light up usually after about 5 miles of driving it or on a hill then after I clear it It may come on again in 50-100 miles seems to do it more at a full tank and then after half a tank gone. p219a shows on the scanner every time occasionally it will throw P219b and a and then once every couple of months it will show the first two codes with a misfire in cylinder 3. now I have done the spark plugs and swapped coils for cylinder 3 and it still shows c3 misfire. I have some screenshots of the data shown when the code happens if that will help anyone figure it out for me. the emissions results when it scanned always have a failed evaporations system, either oxygen sensor heater fail or oxygen sensor fail sometimes both, check engine light fail, and trouble codes failed.

[Doug_Scott]

Check the following

Possible causes:

• Intake manifold leak at a specific cylinder on bank 1.
• Fuel injector issues at a specific cylinder on bank 1.
• Ignition  system issues at a specific cylinder on bank 1.
• Cylinder compression imbalance.

The most likely is a vacuum leak at the intake manifold.  Take a small propane tank and use it to check around the intake manifold where it meets the head.  You are looking for a change in idle speed/roughness.  Since this has been going on for about a year, and started from the day you got it, I have to wonder if this was why the truck was traded in.  You will want to do a complete compression check.  Remove all spark plugs when doing a compression check.  You are looking for a difference between cylinders.  They should be fairly close to equal.  Suggest you not replace anymore parts unless they test bad.  Diagnosis by wallet is rarely successful.

What other codes are you getting? 

[Little lady mechanic]

The code that always pops up is P219A bank 1 air/fuel imbalance then occasionally P219B bank 2 air/fuel imbalance. Then every once in a while I will get a P303. Other then the codes popping up the truck sounds and drives fine. Although on hills it likes to stay in a lower gear so it sounds more ruff and I can occasionally feel that cylinder misfire I think. I have a fixed reader so I’ll attach the last freeze frame from today cause that 303 code popped up again.

[Little lady mechanic]

On 1/4/2021 at 9:36 AM, Doug_Scott said:

Check the following

Possible causes:

• Intake manifold leak at a specific cylinder on bank 1.
• Fuel injector issues at a specific cylinder on bank 1.
• Ignition  system issues at a specific cylinder on bank 1.
• Cylinder compression imbalance.

The most likely is a vacuum leak at the intake manifold.  Take a small propane tank and use it to check around the intake manifold where it meets the head.  You are looking for a change in idle speed/roughness.  Since this has been going on for about a year, and started from the day you got it, I have to wonder if this was why the truck was traded in.  You will want to do a complete compression check.  Remove all spark plugs when doing a compression check.  You are looking for a difference between cylinders.  They should be fairly close to equal.  Suggest you not replace anymore parts unless they test bad.  Diagnosis by wallet is rarely successful.

What other codes are you getting? 

I did just find that there appears to be a bolt in the very back of the bank one manifold there a hole there for one. It appears to have broken off at some point. Could that be the problem? And how would you even begin to remove the stud left over if there is a broken one in there. It’s the last hole by the firewall

[Doug_Scott]

That is the exhaust manifold.  A common issue that will not have an effect on the fuel management/engine roughness.  If you are hearing an exhaust leak you will want to have it repaired.  This is not an easy (as in skill level) task unless the broken bolt has enough of itself sticking out of the head to allow you to use a stud extractor tool to get it out.  The task ranges from being able to get the broken bolt out just by removing the exhaust manifold to having to remove the cylinder head and having a machine shop get the broken bolt out.  If you cannot hear an exhaust leak, leave it as is.

 

 

[Dustin Byrem]

The ethenol % effects mine if I run E85 I get the code almost instantly, will go away running unleaded or premium. Believe it's tied to ethenol % 

[silveradosid]

if you are running regular gas, the ethenol at 20 percent is to high. get someone to reset it