1GR misfires and a bunch of codes

Hi, my 4Runner (V6) is been misfiring occasionally (like a 1 to 3 shakes out of nowhere and then stops) for a week and a half now without any clear sign of what could be wrong, I checked for signs of a worn head gasket, spark plugs and coils with no luck. Is currently 223,000 miles so after that I checked the timing chain, looking through the little window on the passenger side of the engine, it seems like the tensioner is extending a little more than usual so even though it wasn't throwing any code I ordered a timing chain kit and stopped using the truck.

The kit hasn't arrived yet, but today I took the truck out again for a 8 mile trip. It completed the first half of the trip with no misfires and then sat for about 20 to 30 min at the destination, but when I turned it on again to go home it started misfiring, not a single shake here and there like before but a persistent misfire this time... Finally got a check engine light (flashing) and codes P0301, P0102, P0113, P0121, P0123 and P2132. After a few seconds it went back to normal so I baby it home and made it back.

I looked their meanings, being misfire on Cyl #1, MAF and TPS problems, but I'm wondering if there could be another issue causing those codes to come up together since it seems a little odd to me to have non and all of a sudden they come at the same time like is a party. And that how I ended up here asking for advice.

What do you guys think? should I address them as separate problems or there could be a single issue causing all those codes together?

Thanks

 

A few thoughts - simple ones first. Has the throttle body and MAF sensor been cleaned periodically? These are easy tasks, but important ones to keep your engine running properly.

A bit more complicated - at the mileage you have now, since you said you checked for a head gasket problem and found no defects, I would suggest a compression check on each cylinder. Valve seats wear, and eventually it will cause a loss of compression. Maybe only a few PSI, but eventually enough that the ECM won't be able to compensate.

Others will chime in, but without further information, these are a good start.

 

I would do a careful check all the way on the intake section thru the throttle and into the engine to make sure you are not pulling any vacuum and generating either lean or rich conditions. Then try to follow the gas lines and ensure you are not cracked somewhere and nothing looks weird. Think of like doing an overall pressure test of the system and go from there. Hope you find the issue.

 

I clean the MAF periodically, however I have never cleaned the TPS. Thanks for the advise on the valve seats. I didn't consider that.

 

I did this and found that the intake was not properly secured to the throttle body. That could be the source of the codes, leaving the misfire as a separate problem. I cleaned the MAF, secured everything correctly, and reset the codes. I'll have to wait until the weekend to clean the throttle and check the compression and gas lines. At least for now, the codes haven't shown up again.

 

Thanks for your help, guys. Once I'm sure everything is at 100%, I'll post again to confirm the source of the issues and whether they were related, in case anyone else encounters a similar problem in the future.