Morning hesitation/studder

[Forrest97]

I noticed this morning and yesterday morning that while letting the 4runner warm up it starts to studder a little bit after about 1 minute.

It will have this little studder and hesitation until I got off my street and going down the road and giving it some gas.

Possible fuel filter gunked up? Is it misfires? It reminds me of my big carb'd v twin motorcycle on cold mornings when it is starving for fuel and I have to pull out the enricher.

Thanks,
Forrest.

 

[jgue467]

A brief shudder during the warm up phase probably is not related to a timing belt yet I would still want some kind of warm & fuzzy on the belt. I tried finding the same thing out about my rig, no real luck. The 3.4 is a non-interference engine design so no real danger on the belt breaking just an inconvenience...

As for the shudder have you tried cleaning the maf? or at least run some startron, seafoam or other favorite fuel conditioner? This resolved the same issue for me awhile back...

Star Tron Enzyme Fuel Treatment - HOME :banana:

 

[Forrest97]

Thanks for the reply. Im not familiar with Star Tron, is it sold in the stores? I have used SeaFoam but only in the bike.

 

[jgue467]

Yeah you can find it at wallymart for example. I use it on all my vehicles, small engines, quads, so I go thru a lot. An 8oz bottle mixes w/128 gls & costs about $9 at wlmrt. I find it in quarts (covers 512 gls) for about $19 at a local lawn mower shop.

When my 3.4 had that slight hesitation upon a cold startup/drive off, this stuff cleared that issue up on the first startup after filling/mixing this stuff in. Hope it works for you too...

 

[Jumpkix]

Just curious, but when was the last time you had the timing belt done?

 

[Forrest97]

Just curious, but when was the last time you had the timing belt done?

I just purchased the truck last week so I have not had it done. Car fax shows only 3 service records so I assume they did not use a dealer.

It has 210K miles so its possible it was done at the 180K-190K but Im not certain.

 

[ggreyrunner]

I have a T100 with the same motor. Mine was doing the same thing for about a month until it started blowing white smoke. I turns out the head gasket was leaking just enough into the cylinder to make it run rough until the coolant burned off. The leak finally got bad enough to start smoking. My oil and coolant both looked good. I hope that isn't the case for yours but it is a possibility.

 

[Forrest97]

I dont notice any smoke and the little studder is gone in less than 1 mile after it gets some fuel and only in the morning after sitting over night. Doesn't do it when I head home from work.

 

[jgue467]

Those are the conditions mine would do it also, only exception is I'd call is a 'stumble' (engine still smooth just reduced power), for just a second then it would proceed ok.

 

[ggreyrunner]

Mine would do it after work also, so your symptoms are different than mine. I even bought new plugs hoping that is all that it was. I never got to put the plugs in. I let the shop do it during the repair.