[ByrdDog20]

Got an intermittent lightly rough idle on my 2000 Taco 4x4 V6 with 93k miles. You can feel it at idle but I also notice it at higher rpms. I can also put my ear next to the exhaust and hear a miss at idle. Sometimes it seems to go away but only for a few seconds or so. My wife has a 1998 Sienna with 137k and at idle, hers is rock steady and listening to the exhaust, it has no miss. I know we have different engines but they are both Toyotas.

I recently changed the spark plugs, oil, and all filter except fuel. Pulled the plug wires and coils and checked resistance in accordance with the FSM, all checked out good, even wiggled the wires checking for an intermittent break. Ran a tank of Techron, the gas additive, on a tank and can’t really tell a difference. When doing the “Deck Plate Mod” recently I sprayed cleaner on the MAF and wiped out as much of the throttle body as I could reach. The TB was nasty as to be expected on a 2000 with 93k.

Mileage is good. 20-21 mpg and power is acceptable, but the miss is driving me nuts.

Any idea what to check next? I prefer not taking it in to the dealer with an open wallet so they can learn on my truck. I know it needs a timing belt but that has to wait a few more months. Any recommendations on who to take it to in the Houston area?

Thanks

 

[DCabTaco]

The most common cause of a missfire is improper gapping of the spark plugs. I have read that the our trucks can be very sensitive to the gapping and it should be checked closely(wire gapping tool is best). Also check the nut that screws on top of the plugs. A lot of times these are sold slightly loose and that can cause it as well. Good luck and I hope this helps.

 

[ewood]

I have a misfire on cylinder 4 as well, according to the CE code I checked last night, so I am wondering the same thing as well. I cleaned the filters, MAF, and didn't do the gas filter as well. I'm pretty much in the same boat. let me know what sort of suggestions you get because I am interested as well. Good luck.

 

[ByrdDog20]

Just replaced the plugs with the NGK dual electrode plugs listed in the manual, I didn't think there was a way to gap them.

I will look into buying a better gapping tool and checking the gap. I'll let you know if it helps.

 

[DCabTaco]

check this post:

http://forums.delphiforums.com/tacomaterritory/messages?msg=120915.4

and this one:

http://forums.delphiforums.com/tacomaterritory/messages?msg=120915.7

If anyone knows what they are talking about when it comes to the 3.4 engines from toyota it would be gadget. This is why I think that is where your problem may be. If anything it gives you a good place to start troubleshooting.

 

[ewood]

I rteplaced the plugs less than a year ago and this problem has occured sometime after that. I think maybe the timing belt or something, cause I am due for a belt change and timing adjustment. keep me posted and I'll let you know. Thanks buddy.

 

[ByrdDog20]

I gotta respect Gadget, next week I will track down some 5062s and check the gap and caps. May take a week or so, leaving tomorrow for who knows how long.

On a side note, anyone else have trouble putting anti-seize on plugs then tightening them to 13 ft-lbs. I couldn't bring myself to do it, just did it hand tight like usual with no problems so far.

Scott

 

[DCabTaco]

I gotta respect Gadget, next week I will track down some 5062s and check the gap and caps. May take a week or so, leaving tomorrow for who knows how long.

On a side note, anyone else have trouble putting anti-seize on plugs then tightening them to 13 ft-lbs. I couldn't bring myself to do it, just did it hand tight like usual with no problems so far.

Scott

Yeah 13 ft-lbs is not that tight. I think hand tight might be around 13 anyway, but I just went up slowly

 

[ByrdDog20]

Went back and puled the plugs, the caps on top of each seemed to be unremoveable. They were tight and now they are checked and tight. Any other ideas?

Thanks

 

[Windtech007]

check compression possable head gasket