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What could this problem be?

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Old 05-21-09, 10:47 AM
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MuGGzyx
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Question What could this problem be?

Sometimes when I start the car (93 sc400) it seems to sputter and will die if I try to put it in gear and give it gas.
If I turn it off and start it again it will start and run fine. Sometimes it takes 2-6 tries though and is pretty unnerving.
This started a couple weeks ago and doesn't happen all the time, but it's usually at night and it happens 2-5 times a week.

In the last couple days, it has been "stuttering" or loosing power and kind of jerking at speed, like driving down the road, if I accelerate it kind of lags and jerks to accelerate a bit but then smooths out.

I tried Octane boost and Injector cleaner at the advice of a local auto parts guy, in case I "got bad gas", but half a tank later it is still doing it.

This second "symptom" seems intermittent like the starting one, where it might do it on the way to the store a bunch, but then the next time I start and drive it it will run perfect.

I was told that it might be my "throttle plate sticking" but I have no clue what that is. I had the local shop check for codes and I have nothing but a single burnt out tail light right now.

Would a "Dirty Throttle Plate" do this? Could it just be dirty or bad injectors? Would old cables and plugs do this?

Any advice would be welcomed, I just don't want to spend a ton to find out I just needed to clean or replace something easy.

Thanks in advance!
Old 05-21-09, 11:01 AM
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soarer13oy
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could be spark plugs....... maybe its time for a simple tune up. I just did my valve cover gasket and plugs. Still gotta do my distributor ring.
Old 05-21-09, 12:46 PM
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2turbo1sup
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spark plugs, spark plug wires, dirty maf, not bypassing fuel ECU, etc, could be many things.

To check if your throttle plate is sticking, remove the rubber intake hoses and look inside the throttle body. Try moving the throttle cam to see if there's unusual resistance. Spray it with wd-40 if it does.
Old 05-27-09, 11:18 AM
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MuGGzyx
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Pulled and cleaned the MAF, (is it really just the little black plastic stick with the beveled edge on one side? didn't see any wires at all), opnened and cleaned the Throttle Plate, problem persisted.

Pretty sure this is a Plug/Cable thing...

Car has 153k miles on it, I ran into the previous owner last night, since it is rare to run into someone who owned your care before you bought it from a used dealer I asked him about it. Says it ran like a champ the whole time he had it but....

HE NEVER CHANGED THE PLUGS AND CABLES because it was such a pain to do... so that means that the cables and plugs have been in there for around 50K miles... WTF?!? I am suprised they WORK, I am expecting to pull them and see a little ceramic stump with a nub of platinum in the middle now...
Old 05-27-09, 11:23 AM
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The plugs arent that bad compared to changing out your valve cover gasket.
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