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2.5GT lags on acceleration


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Get half a cup of seafoam and pull a vacuum line while someone keeps the car at partial throttle (below 1500). Put the vacuum line in the cup and let the engine slurp up the seafoam. Don't completely submerge it, it should be slurping. When it is done, shut off the engine and let it sit for a few minutes. Then start it up and enjoy the smokeshow.

 

EDIT: Let it idle until the smoke is almost gone then reset the ECU.

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seafoam is a good tool. just dont do it in a city or else people will call the fire department thinking your car is on fire, lol. get ready for a good amount of white smoke from the exhaust

 

were any of your injectors tested? maybe cyl 4 have a partially clogged injector, it will squirt enough for low load but when you get on it it wont flow enough to keep up with all the air entering the chamber causing a misfire in turn causing audible knock?

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I just read this thread, I have the identical symptons with my car, going thru the same exact thing. Had one cylinder 9 psi low, all others normal. Some days it won't even happen other days its terrible. The hotter it gets the better it runs odly enough? Threw a code for the first time this week twice for bad o2 sensor/circuit. Have not had a chance to change it yet. I feel like its not the issue tho. I wanna drive it off the bridge at times!

 

Replace the front O2 sensor if it's giving you a code. I am about to order one off Amazon right now, actually. Worth a shot. It could be a partially clogged sensor or a frayed wire that is getting a better connection with heat.

 

+1 for the car headache!!! I'm going to try seafoam as well (I have a can sitting on my shelf, might as well do it since my new neighbors are awesome).

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We are trying to find a good time and place to do the Seafoam thing. Going to see if the mechanic will do it for him.

 

I have tried again to pull the rom using ECU Flash and still no go. Only thing I can think of is the drivers and, honestly, I don't even know for certain which ones are actually being loaded when the cable is connected. That is on a Windows XP notebook. My son's MacBook Pro running Windows 7 didn't need drivers at all (for RomRaider) but it won't connect with ECU Flash either.

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where are you located? I would see if there are any member near you that are opensource that could try pulling it. That way you can find out if its a problem with your ECU or Laptop...

 

We are in Waterbury, CT.

 

I just gave it one more shot, this time installing "ECUFlash 1.38 for OSX 10.4+" (http://www.tactrix.com/index.php?option=com_content&view=category&layout=blog&id=36&Itemid=58) on a MacBook Pro in native Mac mode.

 

Again, the same results - I cannot read the ECU's rom. I feel that I must be missing something, but don't know what it may be.

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We are in Waterbury, CT.

 

I just gave it one more shot, this time installing "ECUFlash 1.38 for OSX 10.4+" (http://www.tactrix.com/index.php?option=com_content&view=category&layout=blog&id=36&Itemid=58) on a MacBook Pro in native Mac mode.

 

Again, the same results - I cannot read the ECU's rom. I feel that I must be missing something, but don't know what it may be.

 

Damn dude! Wicked big meet was in stafford springs on saturday! Shoulda told us we woulda swung over. I even had my tactrix and laptop with me....

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small update...dumped a can of seafoam into the gas tank, as my mechanic and a couple other local ones refused to do treatment the proper way...drove about 40 miles and decided to stop for an oil change, just to see what it looked like. oil was filthy after only about 1500 miles, and more importantly looked as thin as water. oil change done, started to drive home and noticed significant improvement in the engine's behavior though its also far from perfect. car also stopped idling at 1500-1700 rpm at startup. will post another log after that can is done and continue to seek competent mechanic that listens.
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Yes, I'm sure putting some in the gas will help to clean the injectors and maybe SOME carbon buildup, but at a 12:1 AFR, and a 300:1 (???) gasoline:seafoam ratio, you won't be doing as much good as you could be by putting it through the vacuum lines. Even so, keep pulling LVs and see if they get any better.
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I've had great luck with Seafoam and it's especially good for higher milage cars. It's not going to solve your problem though. IAM is 0 and you're still pulling 11* degrees of timing in almost every cell. People here freak when they see -1.4* being pulled.
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I've had great luck with Seafoam and it's especially good for higher milage cars. It's not going to solve your problem though. IAM is 0 and you're still pulling 11* degrees of timing in almost every cell. People here freak when they see -1.4* being pulled.

 

That's why it would be helpful to be able to check out his ROM. I've seen carbon buildup cause crazy knock on a car which is why I suggested seafoam. Also, if this is something that got worse over time, it would lend credence to the idea that carbon is building up in his combustion chamber.

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I'm in mass and im on vaca all week.....ugh sooo close. tactrix and laptop capable. ???????? OP are you available?

 

and if I do come down I expect single ladies and liquor at my disposal. or, for that matter, maybe some gas money...takes about 1 1/2hr to get to waterbury from here, my sis used to live there.

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Idles rough to the point where it sounds and feels like the engine is missing the rubber portion of the motor mounts. No CEL's, the light does work because we d/c the maf sensor and it came on- the sensor is not at fault either. Pulled some logs and LV's, also pulled his map- its a stock map.

 

At some points during logging i'd go to check the LV and it seems like the ecu was reset(0's across the table)- even though i did not reset it. I checl back again and the timing is pulled again. I'm on my phone, hopefully the OP will post all the files I gave him. Im wondering if the shaking is causing the FBKC to go nuts, so he's gunna check the mounts-

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