Hi and Help

[4RUNTACO]

Hi there, first post!

I like 4Runners and I like Tacomas. I am not a mechanic, but I can fix. If not I get by with a little help from friends. The rest I pay for (more on that later).

I've owned 4 toyotas, 2 4runners (1st and 2gen), and two Tacomas. I've never tricked one out (oh but I will one day), no lift kits - just stock w/ some nice BFGs, and I do enjoy light trail riding up to high lakes for a little camp and fish

I do hope to contribute, but realistically I'm here to learn cuz obviously I cant put the toyota down, so might as well start wrenching on them myself.

Okay so problem child.. I have a 94 4Runner, 3.0 auto. Runs great, idles great, plenty of power (for a 3.0), doesn't over heat, no check engine light/s, seriously just runs great. It does because I just gave lots of money to a mechanic. The 4Runner is mostly for my wife to use as DD, But when she moves on it's my toy to break.

So, It does misfire but I don't notice it at lower speeds. When driving down the highway just cruising between 55 and 70 its smooooth. But if I step on it, If I accelerate it misses and stumbles. It still gets on it no problem, but misfires all the while.

The mechanic did a lot of work/replacing and including, ignition mod, 02 sensor, tps tested good, replaced maf, fuel filter, plugs wires distributor, smoke test, and egr cleaning. Really it's too much for me to remember. And now, he's scratching his head. He gave it back to me and encouraged me to fill it up w/ premium, and add injector treatment - so far no noticeable change.

He did trace the issue to cyl 1, "it fires but not consistently".

So I'm down to a "coil" replacement? Or bad injector? Or a few dozen other possibilities, I guess?

Well there it is, not too crazy but expensive.

Thanks
Jason

 

[theking11863]

Well I'm no mechanic either but I'll give you my best guesses. I could easily be wrong but like I said I'm guessing so no one harp on me if one of them seems stupid to you.

My first guess would be a blown head gasket maybe? I have no idea what the symptoms of one are but you did mention that its a second gen with a 3.0. That just screams head gasket to me as an owner of a second gen with a 3.0

2nd guess would be spark plugs. I know you said that he replaced the wires but you didn't say anything about the plugs so maybe that's a thing. It's possible also that why work fine but aren't gapped correctly. Hopefully that's the problem because it is and easy fix.

Injector might be another cause. not always spraying fuel into the cylinder. Valves too maybe. One goes out you start to have problems. Spark, fuel (gas/air mixture), and compression are the 3 main things an engine needs and without one your screwed. Now because he traced it back to one cylinder it might be possible that it has a compression problem like a leak or something.

I don't know that those guesses will help but I hope they do. Some things you can check yourself easily like the plugs and their gaps. Just look up the correct gap on the internet and you'll be set there