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I've racked my brain and wallet over an intermittent sputter on start up and I'm running on empty, so hopefully someone here can help me solve this.
It all started as a small sputter on cold winter mornings. I started with the simple fixes. Injector cleaners, new spark plugs, and I cleaned my throttle body and MAF.
As time went on, the sputter became more frequent and happened in mornings that were not cold at all. Eventually the sputter became more violent and sometimes killed the engine. I thought it might be a loose belt preventing enough power on start up, so I got a new tensioner and serpentine belt. Then my purge valve solenoid went out so I replaced that and put in a new MAF, then cleaned and oiled my CAI.
Nothing helped and the sputter got worse. It was happening every morning and evening after a shift at work, essentially any cold start now.
After about 6 months of tinkering with it, the car threw a general misfire code and misfires on cylinders 1,3, and 5. I got it diagnosed at a dealership and they told me my timing chain was shot. They wanted $4200 for the chain and water pump replacement.
I opted to do the work myself and save 3k. I got it all done and turned it on. The car fired up great at first, and no misfire codes, but after a few seconds that sputter came back, only now it is softer and less violent.
I'm looking at the throttle position sensor now but I can't find any good tutorials on how to test it. I found one on Amazon for $33 but I don't really want to keep chucking money at this problem blindly.
Anybody have an idea or been in the same situation? I would certainly appreciate it.
 

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This post may not actually help, and by this time, you may have solved the problem. I don't understand your statement about the throttle position sensor. The Throttle body has 2 blade position sensors within it. Both sensors send out a variable voltage back to the ECM based on the actual blade position at all times when the engine is running. If either one craps out or goes haywire, it should set a specific fault code for that sensor as well as your MIL icon. I've never heard of anybody getting their hands on one of those variable sensors, installing same, and then finding a way to set it up precisely.
 
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