Jeffires

I haven't participated on this website in about 7 years. During that time, I started my career, traveled, and undertook other post-college endeavors. I never sold my truck, though I bought other vehicles and it was sometimes a problem to keep so many around. I am so happy I still have it, and now I plan to get back into working on it, and off-roading.

Upon my return to the forums, I would like to post the current status of my ride, and ask anyone who feels like reading a lengthy post for their opinion:

History of truck and current issues:
The truck was not driven very often for a period of about 2 years. During this time, it was not run at highway speed very frequently, and the fuel was probably in a degraded condition.

After I began to drive the truck more frequently, a strong fuel and exhaust smell was present in the cabin. The truck also became hard to start. Once started, it seemed to run fine.

The first round of maintenance included an oil change and fuel drain. The old fuel was drained, and new non-ethanol fuel added. The in line fuel filter underneath the truck was replaced. The air filter was replaced.

Next, seafoam was introduced to the intake via the brake booster line. The engine hydrolocked, as planned, and was allowed to sit overnight. The next day, the engine was cranked and the truck was driven at high RMPs until it quit smoking. Following this treatment, the spark plugs were replaced. Denso plugs were used, gapped according to Toyota specs, and never-seize applied to threads.

After this maintenance, the truck still was difficult to crank when cold. The cold start injector was removed and found to be covered in heavy carbon. The cold start injector was replaced with a used one from eBay. The diagnostic terminals were jumped and the injector fired. The truck became easier to start; for a while. The fuel smell in the cabin continued.

Over time, the fuel smell in the cabin has decreased. It is still present, but much less. The hard starts are occurring again, in hot weather. A rough idle has developed with a very slight surge. At cold or warm conditions, the idle is rough, and surges slightly. Under power, the truck performs as normal. I have driven on the interstate and towed the boat with no problem.

The butterfly valve was inspected and found dirty. Aerosol throttle body cleaner was sprayed into the valve, and it was wiped out. Vacuum hoses were inspected, but no broken hoses found. I listened to the cold start injector with a stethoscope immediately after engine start, and heard no sound from it. I listened to all injectors and they are clicking when the engine runs. The oxygen sensor was replaced (Denso) and the truck driven on the highway for 70 miles. The battery was disconnected during this procedure. Once again, it runs great on the highway.

My diagnosis:
I highly suspect that the EGR system is dirty and may not be functioning correctly. I also suspect that the throttle position sensor and/or the coolant temperature sensor could be malfunctioned; causing a poor air/fuel mixture and contributing to the very slight surge at idle and rough idle. The A340H transmission indicates a code 62 and 63, though the truck shifts properly. I attribute these codes to the possibility that the throttle position sensor is providing bad information to the ECU.

The plan:
I plan to remove the plenum and thoroughly clean it. The EGR valve, pipe, and modulator will be cleaned and tested. The throttle position sensor will be cleaned and tested. The coolant temperature sensor and cold start injector time switch will be tested. The PCV valve and valve cover gaskets will be replaced. The coolant and radiator hoses will be replaced. Everything will be re-installed with new gaskets and Teflon, where necessary. I have read to purchase the PCV grommet and valve cover bolts to replace during this project.

I hope that getting rid of all of the carbon and cleaning out the plenum/throttle body will help. I find removing the plenum necessary to get to the PCV valve and remove all of the sensors I plan to test.

What I am asking:
Does anyone have any suggestions about what else to replace during this job? Is there anything that could be cleaned, or maintenance that should be done? I have used this board many times for ideas in troubleshooting and frequently search it when I have a problem. I been bookmarking discussions for a while now, and I'm getting ready to order parts.

Thanks for taking the time, if you read all of this, and I appreciate any insight.