FastOlds

Hello all- I have a 98 4runner with a 2.7 4 cylinder engine. It has 173k miles on it, and was running great up until a few days ago. I get an intermittent misfire that started only at 70 + miles per hour. Now it misfires intermittently during all speeds, from 25 miles per hour and above. Idles perfectly. When it misfires, it will sometimes throw a flashing check engine light. The problem is, even with a pretty sophisticated scan tool on it, it won't throw a code.

The plugs all look good, i took them out and checked. they all have even, consistent burn patterns. The wires were original, and showed some signs of arching. I replaced them with OEM wires. They didn't fix the problem.

This thing is so intermittent, i drove it almost 200 miles in between occurances. But when it acts up, it seems to do it in bunches. It seems to really happen on acceleration but seemed to do it at steady highway driving.

My thoughts are either a coil or injector starting to fail. If i could get a misfire code, i would swap the coils around and see if it goes to a different cylinder. I haven't ohmed out the injectors yet, but i honestly doubt that it will show anything abnormal.

The funny thing is, i saw a couple of threads on this forum relating to the same problem, but all of the ones i saw offered no solution, the orginal thread starters never came back to fill us in on what actually fixed their problem.

So I'm asking other 2.7 engine owners to help me with my 4runner. This is honestly the first driveability concern this truck has had in over 115k miles (as long as i've owned it!) and it has me stumped. I have access to Alldata and whatnot, but it doesn't appear to be helping me.

Thanks!

raydouble

Have you ever had the valves adjusted?

The reason I ask is that my buddy who works for Toyota says that this happens sometimes.

Might be something to look into.

FastOlds

nope- never have. Normally, i would agree. But in this circumstance, with a non-regular occurance, I think that valves should go down on the list. Unless i am missing something completely.

No abnormal noises and no rough idle.

But I will look into adjusting them in the future.
thanks

FastOlds

well, i was out today with the scanner hooked up to my 4runner. it started acting up real bad, and finally threw some codes. p0300, p0302, p0303- all misfires. Since cylinders 2 and 3 share the same coil, i will swap the coils around to see if the misfire follows to 1 and 4.

I will keep you guys posted.

Bushwhacker

How old is the fuel filter?

Skrillah

I doubt the fuel filter would have any thing to do with this issue.

My guess would be coil pack as well. Have you checked the o2 sensors for proper resistance? Perhaps, a bad one may cause the fuel/air ratio to be inaccurate...although I imagine this would cause a constant CEL.

Definitely let us know what you find...

FastOlds

the fuel filter is a couple of a years old, but not that old. The guys at the Yota dealership laughed at me- they told me that the filter is a lifetime part. How can you call it a filter if it never needs replacing? Anyway, when i took it out, it wasn't that bad. That was somewhere between 135k and 150k. If it doesn't look bad after that long, does that mean all that junk is getting into the engine?

Never understood that.
I'll update you guys soon- when the significant other goes to work tonight, i'll have more time to look at it.

FastOlds

well, swapping the coils didn't help. took it out for a drive, and its missing real bad, but still showing cylinder #3 mainly, with a 302 and p0171 now showing. So looking at the realatively easy access, i took the fuel rail off and ohmed out the injectors. 1, 2, and 4 all were right around 16 ohms. Number 3 ohmed out at 60 ohms.

Being that i'm on a budget, and i work on this myself, i'm probably only going to do the #3 injector for right now. Assuming that the #2 showed misfire just because its companion cylinder was really screwed up, this should fix my immediate problem.

The hardest part of getting the rail out was when i dropped one of the washers for the pressure line banjo bolt. Couldn't find it- hope the dealership has what i need tomorrow.

Thanks for all the input, i'll check in tomorrow with results.

FastOlds

For those that were wondering, it would appear that the #3 injector failed. And it makes me so mad- the stupid truck didn't make it to 200k before having an injector fail! It only made it to 174K before i actually had to spend money on a repair.....

Just kidding about that, it is pretty sweet that it has made it this far without a major failure, besides starter contacts.

The funny thing about the injector is that it cost about the same for an aftermarket replacement as it did for an OEM one- and the dealer had it the next day.

Thanks for all the advice and ideas.
Does anyone know why an 87 Buick Lesabre won't start? LOL.

Skrillah

Glad to hear you are back up and moving nicely!

How much did the injector set you back?

FastOlds

injector listed for $156 or so and i got it for $126 or so. I get a little discount, although for as much money as i spend there you'd think i'd get a little more. As easy as it is to do, i'm gonna only do one at a time- hopefully this isn't going to be a trend with these. Maybe the next one will last another 173K before failing.

I'm still psyched that I got that many miles on an original set of spark plug wires. I replaced them, thinking they were the problem due to carbon tracking. Could've probably gotten 200k out of them before replacing.

The 2.7 is an awesome engine- not powerwise, but just in the overall awesomeness of it.

Skrillah

Well again, glad to hear you got it figured out. You started to make me sweat for a bit thinking man...if this guy needs his valves adjusted or something I'll have to put that on the short list and hold off on the other mods...

The 2.7L has been proven to be a worthy engine for me as well. I try not to get on her too hard as I know I'm really not going to get there any faster! I drove the 3.4 at one point and honestly couldn't tell a HUGE difference at least in town driving. Definitely more there in the mid range and i'm sure on the highway but overall I wouldn't say the 3.4 is a v8 compared to the 2.7...just a v6 kind of upgrade...if that makes sense.

I'd still go for the 3.4 in a heartbeat...lol...if given the opportunity but I have been happy with the 2.7. It hasn't let me down yet!

Cheers

FastOlds

Well, i put the injector in yesterday afternoon, and have put a bunch of miles on it. No problems to report.

And I know that the 2.7 isn't the most fastest engine out there, but it is still an awesome engine. Easy to work on, no timing belts, and an all around standup engine.

I think mine is starting to leak a little oil- but not enough that i'm concerned about it to make a production out of it.

My 4Runner has been the best vehicle i've ever owned. Don't tell my Oldsmobile buddies I said that.