Still misfiring

I posted months ago about my cylinder 2 misfiring upon start up in the cold(er) mornings. Upon recommendation of my mechanic, after hearing the symptoms I was having, and to save money(pfft yea right!), we decided to replace the fuel injectors. Ran me upwards of close to $1k with parts and labor. Now when I start it up in the morning, a lot of gas gets starts flowing now. If I just let it idle and warm up, sometimes it will misfire again, but if it's warm enough out, it won't. I can also rev the engine while it's warming up to avoid the misfire. It starts to run a bit rough at first, if I don't let it warm up all the way. I can't punch it right away, it won't engage until it warms up. But once I am able to punch it,it seems to work fine. The only thing is now, it won't start up again smoothly after I turn off the engine, the engine won't turn over right away. But if I push the gas pedal about 5 times before I start it, it will start up...albeit not smoothly a lot of times. Oh, and when and if it misfires sometimes, I have once gotten cylinder 3 misfiring instead of 2, but it is mostly cylinder 2 all the time...IF it misfires. Cylinder 2 has already been replaced along with the coil,etc...along with all the other cylinders with a tune up a few months back.

 

Are you loosing coolant?
Have you done a compression test on a cold engine?
Leak down test?

 

I assume none of the above. I'm sure the mechanics have done all that.

 

Really, you shouldn’t have had any change in behavior just from changing the injectors if they weren’t the source of the problem to begin with. I doubt they were in bad shape since you were reporting a misfire and no other problems. But now that you have more problems, the first thing I would suspect is the new injectors. Were they aftermarket or OEM? The other thing that could be related is failure to hook up a hose or something like that when the work was done.

Are there any codes? Might want to check the fuel trims while driving.

 

Yea, the engine not turning over started happening after they put in the new injectors. I'm pretty sure they were new, cost me over $500 for just the injectors. As far as the fault code, it is usually always cylnder 2 misfire. Forget what the exact code was, P3something, but it said cylinder 2 misfire.

 

Probably P0302
I hate to say it, but it sounds like your mechanic threw parts at it a hoped for the best.

 

Yea that's the code. And I don't think my mechanic did that. They are a highly regarded establishment. I just went down to talk to him again, and he says he may know what the problem is with the engine not starting again easily enough after turning off. As far as the P0302, I can bypass that if I warm the truck up enough before driving...and revving the RPMs up when it starts up in the morning. I'm taking it down there again next week to have him look at it again. I think my main problem I'm concerned with now is the not restarting easy after turning it off. But like I said, he says he may know what that is. Won't charge me he says.

 

You need to inspect the cylinder when cold. If you have “lots of fuel” on a cold start. You might have an injector leaking.
Are you sure it’s fuel? Coolant can cause a misfire too. The head gasket usually leaks when cold and then seals up once hot. At least at first.

You need a thorough diagnostic.

 

Thanks for the response. Yea, I'm sure they will do another diagnostic for it next week when I bring it in. My mechanic told me to pass along any info you guy could come up with too. For all I know, they already did all the things you guys have listed. My truck only has just over 50k miles on it, so one wouldn't think that a head gasket is going bad yet? But I will pass all this along to them. Thx

 

You would think so, but things happen.
At this point you have to rule everything thing out with a diagnostic. You’ve basically replaced all the ” obvious parts”
Now it’s on to the not so obvious.

 

Have you carefully checked all the wiring up to the second cylinder COP to see if there are any abrasions/damage from rubbing on something, burning through from something, etc.?

 

New to Tacomas but not engines…the restart issue says to me there is either too much fuel or coolant. Being that you have all new injectors and the misfire issues I would lean towards a possible head gasket. Double check compression test was done. Any smoke on start up or when you notice a misfire?New injectors probably helped a bit because of an improved spray compared to the old. Only thing that makes sense unless one was leaking.

 

Thanks for the reply, I will pass all of this along to him/them. I think they would have already thought about and checked all the things listed in this thread, they have done diagnostics on my truck,and they are a very good and reputable business here. But you never know.

 

Certainly assuming a reputable shop like you stated in my thoughts. I do like the thought by someone above about frayed wires too. I had a similar problem with an old RX7 years ago...it was a common problem with them where the combustion chamber would get flooded and had to put a shutoff for the fuel injectors so it could be cranked to clear the fuel. Not suggesting that as a solution here.

 

Pull spark plug #2 and post a pic. If it looks wet then that injector is leaking.

 

Thanks, I will pass that along on Thursday when I take it in. But I know they have already pulled and replaced that plug, as well as the coil. So I would think they would have seen the above. But as I said, I will pass it along. Thanks

 

Update for today.. Started fine, no check engine error, drove fine from the start even with not warming it up all the way. Truck restarted fine after I stopped it for a few minutes. But it also wasn't as cold in the mornings as it has been recently. And my problems always seem to arise when it's super cold out...P0302 at least.

Oh and btw, concerning that above comment about smoke when I start it. When it was super cold out, I did notice a lot of 'exhaust' smoke when I pushed on the gas pedal. But today I didn't really notice it.

Just went out to try and restart it again after letting it sit of a couple of hours. Had a hard time starting this time....

 

Question,as per the cylinder 2 misfire. Would driving a tank of gas all the way to almost empty all the time create this problem?

 

Nope

 

Have them verify the plug gap on spark plug #2 as well.