Check engine light on well maintained truck

2000 4-cylinder, extended cab Tacoma

The light came on this morning and it gave me the motivation to get some work done that I've been planning to do for a while. In the process I cleaned out the MAF sensor and checked for vacuum leaks. Replaced all the gaskets from the head up (not the head gasket itself). Replaced spark plug wires and plugs, new belts were due too. Cleaned out a bit of sludge but the light stays on. Engine runs smooth and no decrease in mileage. Gas cap is on tight. Is the only way to really determine what's going on by getting a code reader? I tried everything I could find info on but light stays on.


As for the sludge, I change my oil every spring and every fall, only drive about 6000km a year but in a cold climate. That means lots of idling. The sludge was localized around the back of the engine, where the PCV valve is. I scraped most of it out but obviously couldn't get 100% of it. My plan is to now change my oil every 2000km or 3 months whichever is first with a high detergent oil. Or I could do an engine wash additive thing but I'm weary of that due to clogging oil line possibilities. Open to suggestions on this matter

 

Get a code reader. Canadian Tire puts them on sale quite often.

 

1. Yes you'll need a code reader.

2. I'd suggest trying Valvoline Restore and Protect and sticking to 5k mile oil change intervals.

https://www.walmart.com/ip/Valvolin...nB1Ro61jYP4Em3R64ib5uzR4tctwmivwaAhDKEALw_wcB

 

Many auto parts store will do a free code scan in hopes of selling you a part. Dont fall for it. If you do go this route get the code and ask for the freeze frame data. When code(s) are set the PCM stores the data that triggered the code, this is usually more informative than the code. Use your phone and take a picture of the screen(s) and upload them here and advice will be given.

 

Where was this sludge you are concerned about? In the intake manifold? That's not really sludge that increasing oil change frequency will help improve. Build up in the intake manifold is due to the PCV line, and if equipped EGR.

 

I interpreted what OP said to mean the sludge was under the valve covers just inside of where the PCV hose exits, but perhaps thats not what he meant

 

Well maintained, while admirable, doesn't mean that things won't still happen. As said above, get the codes read.

 

You are correct.

 

Well in that case high quality synthetic oil with good detergents, changed every 5k miles or 6 months (whichever comes first) is about all you can safely do

 

CODES!!!!!!

 

Yep. No matter how well-cared for, engines are mechanical devices that will wear out over time.

 

Yeah I am aware, I wasn't saying so much as it is so well maintained that how could anything possibly go wrong, it was more a question of what is a common issue that could occur to an otherwise well maintained truck.

Will get the codes read

 

What is the general consensus on engine flushing products such as liquimoly/seafoam etc?

 

Are you trying to solve a specific problem? If no, don't bother. Unlikely to hurt (properly used), but also you're going to be spending money for no return.

 

These old trucks will toss codes every now and then it’s just the nature of driving an older vehicle no matter how well maintained. Without the code though we are just shooting in the dark. Generic code readers are cheap and an extremely valuable tool to have on hand with an older vehicle, rather than having to rely on a parts store or shop to do it every time one pops up

 

Yes, rubber, plastic, and electrical parts all could fail around the engine with 25 years of rot and heat cycling. Could be any one of 50 reasons you have a CEL. Get a scan tool, read codes, and look at live data. Blindly shooting the parts cannon any further will do more harm than good.

 

I think if there's enough of something built up in your engine to want to flush it out, then your likely to cause issues by using a strong flushing product. Hence why I suggested just relatively frequent oil changes with high quality oil. Anything more aggressive than that seems too risky in my opinion

 

How hard is it to get the codes read?