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Old 04-08-2010, 11:09 PM   #1
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Default Four Codes, rough idle, hard starting

My girlfriend has a 97 Bonneville SE with 130k miles and it'* been giving her fits lately. It'* gradually gotten worse. It'* hard starting, surges up to 2k rpms at idle alot, and seems to be even worse once it'* been drove and warmed up a bit. It got a tune up probably 30-40k miles ago and the fuel filter only has a few thousand on it.

I scanned the codes and got the following....P0300 P0121 P1406 P1655.
The P0121 might be fixed already because it had this code before and I installed a new TPS, but forgot to clear the codes. It'* always had P1655, but the P0300 (random misfire) and P1406 are both new since we last checked it a while back. First thing I did was clear the codes and then drove it about 10 minutes to my house. The only code that came back right away was the P1655, which from what I've read wouldn't cause any issues with how the care runs.

Also I pulled the hose off the Fuel Pressure Regulator and smelled it after it had sat 10 minutes after being driven and it had a strong gas smell which makes me think it might be bad. It did not leak fuel though, but the hose tip did look a bit moist.

Where do you think I should go from here to try and get it running better?

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Old 04-08-2010, 11:17 PM   #2
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Start with cleaning the throttle body, MAF, and IAC. After these are all clean, see if it'* better.
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Old 04-09-2010, 09:11 AM   #3
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The codes you listed are pointing mostly to a vacuum leak. The hard starting and other symptons join in the fun as well. The P1406 being an EGR pintle error code could be giving you the info you need.

I'd pull the EGR and check that the pintle valve moves freely for starters. Pretty sure you'll find it'* stuck and leaking vacuum. That will likely clear up all the other remaining codes.
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Old 04-09-2010, 09:35 AM   #4
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Thanks. I will try that out first. These issues have always been intermittent. One day it won't have any trouble, but then the next day it will be a bear all day long.
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Old 04-09-2010, 09:41 AM   #5
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If the pintal is sticking just a bit that will explain it. One day it sticks and one day it'* fine.
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Old 04-09-2010, 10:26 AM   #6
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Agreed.. carbon build up.

Plus the PCM will actuate the EGR up and down repeatedly trying to clear a stuck pintle before tossing the code.
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Old 04-09-2010, 08:28 PM   #7
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There was a lot of carbon on the pintle and inside the EGR as well as the tubes that the EGR hooks to. I had some throttle body cleaner on hand sprayed it on the pintle and EGR and used a small brush and screw driver to scrape off the carbon. It was nasty!

When I let the EGR sit for a bit and then push on the pintle, it seems like it'* stuck open and takes a bit of force to close it. Should I get something to soak the bottom of the EGR in to try and get the pintle to move easier or just keep spraying cleaner in there?

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Old 04-10-2010, 02:17 PM   #8
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I bought some more carb cleaner and let the cleaner soak on the EGR pintle and inside and it seems to be moving a lot smoother now. This is something else I noticed. A boot was cracked on this hose. It'* the one that connect to the FPR and a few other spots. The yellow circle boot is the one that is cracked. It is really loose on there.

What part do I need to buy to replace this? I looked on rock auto but couldn't find it.

Thanks
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Old 04-10-2010, 02:28 PM   #9
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You can try to find one at a local salvage yard, but it may not be in much better shape. Otherwise I think your going to have to go to a dealer. Try a auto parts store.
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Old 04-10-2010, 02:30 PM   #10
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Thanks. I had a bunch of other questions, but I noticed the tech section of the forum and it had a bunch of how to'* on performing maintenance. This site is great!

The only thing I looked for and couldn't find was an article on how to remove and clean the throttle body? I'm sure I just over looked it, but could somebody link me to it?
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