Changed Spark Plugs, engine stalls

I have an 03', V6, 4x4 Pre-Runner with 175k.

I just changed all 6 spark plugs. My engine ran fine for a mile test drive. However, about an hour later, I attempted to start the engine again and it cranked excessively. After it turned over, it began to rhythmically vibrate the truck while in reverse. Once I put it in drive, it completely stalled.

Within the last two weeks, I have replaced my battery, fuel pump, fuel and air filters for other reasons. The truck ran fine, but the spark plugs really seemed to disable it.

What is most commonly done wrong while changing spark plugs that would cause these symptoms?

Any advice is helpful. thank you.

 

Possibly cracked one and it didn't show itself right away.

 

Did you change the wires? If not (or even if ya did) re-seat them and check the order!

 

Did you check the vacuum lines; did anything get knocked loose?

 

Welcome to TW! In addition to the question already asked, did you use the correct plugs and were they properly gapped?

 

This. The correct plugs are critical. NGK double ground plugs are the best.

 

Or when in doubt, go to the dealership and buy the toyota OEM plugs to be sure.

 

NGK and Denso ARE what Toyota installed in our trucks.

 

whats even the point of using 2 different manufacturers for plugs? are they just so good that toyota couldn't decide which to use and finally said

 

I noticed that too. The reason I suggested using the plugs you get at the parts counter from the stealership is because it just makes things easier (simpler). I don't see any advantage to going and buying 2 different brands of plugs. The fact that they used 2 different brands tells me it was purely to keep cost of production down.

 

One thing you may check... If you accidentally drop a spark plug into the head instead of lowering it with a spark plug socket with a rubber grommet, the gap can sometimes pinch shut. This would basically give you a dead cylinder.

Also check to make sure you have a firm interface between the spark plug wire and the top of the spark plug... but I am sure you guessed that already.

 

To be clear, I was not advocating continued use of two different kinds simultaneously. My intent was simply to point out that both NGK and Denso (recommended in the The Truth About Spark Plugs.... thread) are OEM. I've run both with good results, and don't think you can go wrong with either one.

 

FYI Toyota used both NGK and Denso at the same time in the 3.4's. They came from the factory with NGK's (7787,

$10 LFR6C-11 V-Power Spark Plug, Pack of 1

LFR6C-11) on the passenger side and Denso's (3381, K20HR-U11) on the drivers side. Its OK to change all 6 to either one.