My check engine light came on the other day and flashed a 1/2 dozen times and then stayed on. After pulling the code P0308 (cylinder 8 mis-fire) I cleared the codes and the the truck drove fine.

No issues until a few days later and the truck started and idled rough then ran smooth. Pulled the # 8 plug and all looked normal to me. Cleared the codes and drove fine for a few more days.

Today I have the following 5 codes:

P0308 Cylinder 8 misfire detected

P0132 O2 circuit High Volt (Bank 1, Sensor1)

P0154 O2 circuit no activity detected (Bank 2, Sensor 1)

P0300 Random misfire detected

P0308 Cylinder 8 misfire detected

Some of the symptoms I have been chasing down are:

(1) The truck has been slowly loosing coolant w/o a puddle under it. (typical water falls in heater core) - replace the TB heater gasket and still loosing coolant.

(2) Only seem to get the mis-fire / rough idle after a cold start (truck sits over night) not while driving , nor after restarting once warmed up.

Services are as follows:

Wires were replaced wires with Magnacor 8mm @ 104,850 miles

Coil was replaced with an OEM coil at 104,850 miles

Plugs were replaced with Bosch Platinum Plus 4 at 215,513 miles

Head gaskets were done at 179,317 miles

original O2 sensors

Some things I though of are (1) I could be loosing coolant into cylinder # 8 causing a mis-fire .... but there are no signs of smoke in the exhaust (2) it is time for new wires / coils again (3) time for O2 sensors... but doesn't explain the mis-fire????

Any thoughts?

 

If you are getting coolant in #8 the plug will be unusually clean. Also you can perform a carbon monoxide test to confirm CO in the coolant.

 

how do you perform a carbon monoxide test on coolant?

 

It is a chemical tester. Changes colors if CO is present. Commonly referred to as a Block Tester

 

Take the plug out of #8 and look at it. If it looks super clean or has an odd look compared to the other plugs you probably are losing coolant into the cylinder. Does it blow white smoke when you fire it up? My vote is you hit it on option #1.

 

You seem to have multiple issues at once.

No issues until a few days later and the truck started and idled rough then ran smooth.

Was it a hot restart or cold restart.

Pulled the # 8 plug and all looked normal to me.

Define normal cuz what looks normal to some could be fubar to others. Did you compare it to another cylinder

P0308 Cylinder 8 misfire detected

This one is pretty obvious. You have a misfire on cylinder #8. Like everyone else says, pull the plug and compare it to another plug

P0132 O2 circuit High Volt (Bank 1, Sensor1)

May be incorrect but this may be the sensor picking up the gas as the cylinder misfires

P0154 O2 circuit no activity detected (Bank 2, Sensor 1)

That my friend is known as a dead O2 sensor. 230,000 miles you say on the originals. I think its time for a replacement. All of them

P0300 Random misfire detected

Gonna get that when any cylinder misfires

(2) Only seem to get the mis-fire / rough idle after a cold start (truck sits over night) not while driving , nor after restarting once warmed up.

That indicates to me that your headgasket is leaking. Its collecting in the cylinder overnightand when you start it in the morning, voila. Instant misfire. Before you go replacing parts like people love doing on here, follow these steps.

1. Pull the plug. Inspect and compare it to another plug.they should look the same.
2. Buy, Beg, Borrow, Steal or Rent a borescope and look into that cylinder. then compare it to another. If #8 looks nice and shiny and #6 for example looks like it lives in a coal factory, you have found your problem.
3. Replace your O2 sensors. All of them.... i think its time.
4. Report back with your findings

 

Drove the truck all day today w/o an issue. Cold start this AM - no CEL
Then drove 65 miles to work no issues. Warm starts throughout the day no issues. Then cold start for 65 mile drive home and no issues.

I'll pull the plugs and take photos for others opinion.

Also, i've been looking at replacement O2 sensors. Read some posts about local auto parts stores & ebay stores having replament sensors that have issues with the pig tail connections. Should I stay away from those and go with Atlantic British or British parts of Utah? Any suggestions?

Also, does a standard socket fit on the sensor? - if so what size?..... or is a special socket needed to remove them?

 

With the mileage and all the work done on it, if you still have problems, send me your number and we should talk. At your mileage, you cam and the majority of your valve train is shot as is your timing chain, fuel pump and oil pump, so plan on putting some time in her if you want to get that sort of mileage all over again.

 

not sure if I agree with the valve train comments. the truck has been trouble free for me and it runs realy great. I am the original owner and have used nothing but synthetics in her. I have changed the valve cover gaskets at about 150K and the top end of the motor / rockers were super clean. I have no signs of smoke, no loss of power, and no leaks (oil, tranny fluid, P/s fluid, etc) Coolant is minor and I think I solved that one with the TB gasket changed now.

Drove her all day today and no CEL. good news so far. I'll post again If I see the code(s) again.

 

Thank god you didnt agree with the valvetrain comment. But moving onwards, im assuming still no cel. Did you ever get a chance to pull the plugs? As far as O2 sensors are concerned, you can do it with a regular wrench, but it will be a pita. You can also pick up an o2 sensor socket at most auto part stores