Small misfire

N

NCrunner2012

New member
So I have recently developed a small misfire when I take off from a dead stop. I can take off really slowly and it won't happen, but if I try to take off with any force it will sputter.

I don't have any CELs but about a year ago I did have a CEL for my TPS sensor but I never replaced it because the light went out (it does still work though).

Will a bad TPS cause a misfire?
 
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About 6 months ago, maybe 7k miles max. They are NGK something's. I can't remember exactly. They were the most expensive ones they had if that matters.
 
Check your plugs. See if you have one that is fouled. You could have a bad plug wire, coil, spark plug or in Doc's case - a bad fuel injector.
 
Singtoe said:
Check your plugs. See if you have one that is fouled. You could have a bad plug wire, coil, spark plug or in Doc's case - a bad fuel injector.
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So I ended up taking the plugs out and noticing I put in single electrode NGKs so I swapped them out for double electrode NGKs and went down to Toyota and got new plug wires and an air filter.

Success, misfire gone!
 
NCrunner2012 said:
So I ended up taking the plugs out and noticing I put in single electrode NGKs so I swapped them out for double electrode NGKs and went down to Toyota and got new plug wires and an air filter.

Success, misfire gone!
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That is great but the world will never know if it was a bad plug or a bad wire.

As soon as the new shop is done, we will have to have another get together for a meet and greet.
 
Actually guys i installed just the new wires first and there was no change. That is what made me do the plugs again. I should have been more clear. It was definitely the plugs!
 
So a new problem has shown it's face. Today as I was driving about 45, I was accelerating to pass another car and I got a wicked shimmy almost felt like a misfire, but I'm thinking it may be more. It's got brand new plugs and wires and I'm leaning towards possible u joint play or driveshaft issues. If I let off the gas it would quit and I could ease into it again and it wouldn't shimmy. This is beginning to get annoying.
 
PitbullRescuer said:
U joint wouldn't matter how hard you're on the gas, just the speed of the driveshaft. I'm pretty sure you have a bad MAF.
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Remember I was getting a TPS code thrown. Could this be my whole issue? I have no code right now, but I did a few months back. It just went away on its own. I hear a bad TPS can give issues like this. The voltage drops at a certain level of throttle causing a misfire feel in a way.

Thoughts?
 
Do you have the FSM? I believe you can use a multimeter to measure the resistance of the the throttle when it's closed and at WOT, and see if it those are within specs. Also, perhaps cleaning the MAF sensor would help.
You mentioned you changed plugs and wires, but what about the coils?
 
I went ahead and replaced the TPS to see if it would make a difference, it's hard to say if it helped or not. It seems better because it is happening much less as well as not as distinct, but the problem is still there. I'll clean the MAF and see how goes.

Tonight I got a flashing CEL while on the highway. It flashed maybe 4 or 5 times then went out. I'll go have the stored code read tomorrow and see what it is saying.

So the list of replaced parts go:

Plugs- dual electrode NGKs
Wires- OEM Toyota sumitomo
Air filter
TPS sensor

Problems:
Shudder/stutter when accelerating around 45mph
Flashing CEL twice
Slight hesitation starting from a dead stop
 
If it has an egr valve, pull it off and make a flat thin "block off plate" from a piece of thin metal. Make it the same shape as the gasket, then bolt it in between the egr and the manifold. If your problem goes away, replace the egr valve and gasket.

Over time they carbon up and they can become weak. Based on the symptoms you describe and the parts you've replaced, it may be what you're experiencing.
 
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