Engine lag?

[Luke the Dog]

Ok, 3 days ago my runner started doing something strange. When I step on the gas, from a stop or low rpms, it will do this weird lurch/lag sort of thing for just a moment, then once it gets higher in the rpms it feels fine. It doesn't do it every time, maybe 50%. I checked the radiator, no milkshake, and had the tranny flushed because it needed it anyway. Almost feels like maybe the engine is not getting fuel or something? Has anyone had issues with fuel filters or fuel pumps? I'd rather not have to take it into the shop...

 

[cordrayj1]

give the ole fuel filter a break and replace it. cheap.

and if you flyfish, which i assume you do, im coming out to CO in the next few months and would love to get on some fish.

 

[HCurphy]

I know this is a difficult item to search for, but the info is all ready out there. So, give google another shot. I know yotatech has quite a few similar threads. (Im having the same issue and having a hard time collecting a lot of conclusive information about it)

I'm not a search nazi though, so here is my attempt to help.
http://www.toyota-4runner.org/probl...uttering-under-full-acceleration-2k-rpms.html

edit: There is some good info in that thread, and the FSM can be helpful for some of the diagnostic procedures--that guy even attempts to translate some of the "FSM speak".

 

[theizzardking]

give the ole fuel filter a break and replace it. cheap.

and if you flyfish, which i assume you do, im coming out to CO in the next few months and would love to get on some fish.

should do this anyways, but i wouldn't suspect this of being your problem unless you been using some pretty nasty fuel over the years, i have yet to see a member report an issue arising because of the fuel filter, more along the lines of increased mpg's when swapping it out as opposed to having an issue and NEEDING to swap it out....


that said, i would start to suspect possibly a partially clogged fuel injector or even much more simple possibly just tighten your throttle cable and see if that sorts it out for you, could be the cable is just loose and slipping on the pulley before it tightens up enough to grab and be ok...

give it a search of testing fuel injectors and see if that helps, but really the easiest most simple thing to check is the throttle cable first.

 

[Luke the Dog]

So new development today, I got the sputter while cruising at 55-ish at low rpms. This is driving me NUTS! Throttle cable seems fine, going to try the fuel filter tomorrow I think. Now that you guys mention it, it could be injectors I suppose. If I park and rev the engine I think it lags right at the start of the revs, but it's way more noticeable if I'm in gear and moving. Don't notice a difference if I turn on the ECT, and when rolling the revs drop instead of spike so I'm pretty positive it's not a tranny thing..

 

[theizzardking]

So new development today, I got the sputter while cruising at 55-ish at low rpms. This is driving me NUTS! Throttle cable seems fine, going to try the fuel filter tomorrow I think. Now that you guys mention it, it could be injectors I suppose. If I park and rev the engine I think it lags right at the start of the revs, but it's way more noticeable if I'm in gear and moving. Don't notice a difference if I turn on the ECT, and when rolling the revs drop instead of spike so I'm pretty positive it's not a tranny thing..

Well that sucks now you're stuck chasing sensors or fuel delivery issues, how handy are you with a multimeter ? Its could be a throttle position sensor issue as well , but i would check injectors first , seems to only happen at low rpms so that could be when the signal to the injector is weakest sending the least amount of pressure through the line and if partially clogged would cause a studder , when you give it gas the signal gets stronger increasing the fuel pressure at the injector and would be less noticed at higher rpms and not dependent on speed . This is just a guess but seems logical, i just can't figure out why you're not getting a cel of some sort...seems much more likely to be an injector because of this though besides a sensor failing and not throwing a code . Other guesses would be to check tps and maf with a meter .


There's a bad ass write up here on removing,cleaning and replacing things injectors if you give it a search . One last thing it maybe a good idea to very carefully cut open the old fuel filter and see how dirty it is , may give you an idea as to the condition of the injectors and inside of your fuel lines .

Any other ideas out there would be great...

 

[Luke the Dog]

A multi-what?

I'm pretty comfortable wrenching here and there, bolting things on, wiring up lights, etc., but once things affecting the enging started getting involved, sensors and such I'd take my trucks into my awesome mechanic. Now I live 2 states away from him and don't know anyone good here near Littleton yet. If I can find good instruction on something I'll take a swing at it though.

I like your reasoning on the injector, especially about higher pressure at higher rpms--that and the fuel filter will probably be my list of things to do tomorrow...

 

[Luke the Dog]

Well, only was able to put in a new fuel filter yesterday, before I had to go to work-not sure if it made much of a difference yet. Also put in a fresh tank of fuel, thinking maybe it was just a bad batch that caused all this. Going to try some injector cleaner additive to see if that makes a difference...

 

[Killa-Cotton]

Sounds like the TPS or Mass Air although I would think the CEL would come on but I've the same problem (on a nissan) no CEL and it ended up being the Mass. I'd try to clean the Mass and a Seafoam treatment couldn't hurt either.

 

[Diagram14]

I second the 10 min MAF job. I had a pretty bad accelerate sputter when I first got mine and a quick clean cleared it all up. However, I dont know what that will do with the new cruising sputter you've developed...

 

[Luke the Dog]

Thanks for the input guys, I'll try the MAF cleaning as well. No CEL showing up, so I'm kind of starting with all the smaller fixes I can do myself before I take it to a shop...

 

[Luke the Dog]

Cleaned the MAF, it was real dirty on one side, but the issue did not go away! I put a Chevron fuel injector cleaner in the tanks when I filled up yesterday, we'll see. The CEL flashed times in about 2 seconds as I got on the highway on an uphill onramp, but hasn't come back since. If the CEL doesn't stay on, would a dignostic show any codes?

 

[Luke the Dog]

Replaced the spark plugs and wires today with NGK equipment. I think it solved the problem I was having, didn't experience any of the sputtering/lag issue on the 15 mile drive home. Crossing my fingers! All the plugs I took out were Denso, so apparently the plugs had been changed before, or at least three of them. Below are pics of the MAF before and after cleaning, and one of the old plugs next to the new one...