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moonlitdriver 01-16-2013 03:55 PM

2005 zx3 2.0 Duratec stutter/shudder
I have a 2005 zx3 2.0 duratec with 5sp. Car is stock with stealth CAI just modded to see if would help my issue. Car has 113000 miles and im the only owner. Lately the car has a very loud engine noise under load and acceleration. With that there is a stutter/flutter to the engine under load, at any speed. Mostly noticeable at highway speed with any throttle. noise and shudder subsides as soon as throttle is released. Have replaced the fuel filter and new autolite plugs gapped to .55. Coils all have 4 ohms resistance. Going to clean MAF tonight to see if it helps. I am stumped. Also...ECU was reset after new air filter and plugs installed and went for 120 mile highway drive to let the ECU relearn.

elsolo 01-16-2013 05:06 PM

Without more information, all we can do is take a guess at what could cause it.

TPS sensor could cause what you are describing. You can back probe your's to check the voltage, or try a different one.

moonlitdriver 01-16-2013 06:47 PM

I will try and test voltage later tonight are there static values for zero and WOT? Was told by a friend voltage should increase steadily throughout the range of the throttle plate. Is this correct? The car runs like this no matter what octane fuel (have 93 in tank now, tried 87 and 91 with same results) also have put injector cleaner in every few tanks since owning. Fuel rail pressure sensor does not smell like gas and voltage does fluctuate with vacuum change(cant find what the values should be reading though. Engine has some valve noise but not bad (sounds norm). Car has original fuel pump. I do think the passenger engine mount needs to be replaced (has some vibration).What other information would help?

moonlitdriver 01-16-2013 09:00 PM

TPS read .79 at closed position and 4.6 at WOT. Voltage increase seems fairly smooth from idle to WOT positions. MAF cleaned and real change with the flutter under load. Seems to be moat noticeable above 2500rpm. Still no CEL.

whynotthinkwhynot 01-16-2013 09:33 PM

Change your coil boots. Those aren't designed to last more than 100k miles. I replaced mine at 80k. It had a "stutter".

moonlitdriver 01-16-2013 10:58 PM

The boots seem fine. No cracks or anything. But I'll look into that on payday.

moonlitdriver 01-17-2013 05:45 PM

Don't know it makes a difference but took back road to work today...bumps in the road seem to increase the problem. Could this be related to a cv or drive shaft issue...or even a rod bearing?

whynotthinkwhynot 01-18-2013 05:11 PM

Rod bearings aren't affected by bumps in the road.

The valve noise you are hearing is most likely not valve noise. Use a mechanic's stethoscope to listen to the valve cover, and it will most likely be quiet. Listen to the intake manifold, and you'll hear the noise. That's the tumble flaps. If you do this diagnostic, and find what I wrote, then start a thread asking about tumble flaps.

CV axles don't typically cause stuttering or stumbling like you referred to. Vibrations can be caused, but it's doubtful that those would be severe enough to seem like the engine is being affected.

moonlitdriver 01-21-2013 08:40 PM

I did look into tumble flaps. Mine have some noise, but still unsure its the real cause of my problem. The car continues to run like total s*&! I did notice one of the plug boots was a little melted where it meets the coil. New boots on the way. is a link to the odd noise under load. I still think it could be a bearing.
Any other suggestions?

moonlitdriver 01-21-2013 08:53 PM

Also the noise comes from passenger side of the engine. Could the timing chain or tensioner be so worn/slack that its hitting something? (Had an old toyota that had that happen, but it had 295k miles on it!)
Hopefully picking up a truck soon to use as winter vehicle and daily driver to be able to work on possibly dropping the pan and having a look in there too.

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