Intermittent surging / bucking problem p0103.
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Intermittent surging / bucking problem p0103. Hopefully someone can help me figure this out..
A few days ago I took my car to my tuner to get the idle set with the new accufab tb for the TPS and IAT. Everything was dialed in pretty good... car ran ok, also did some fuel trims, basically a small street tune to break in the motor and clutch before hitting the dyno.
All of a sudden it started bucking and surging really bad at any RPM under about 2500. Way more then you would expect even for a mid 260's cam, and I started throwing a p0103 code (map reading high). Car also wouldn't find idle, would constantly try to die.
Did it for about two days. Now, about 150miles later, this morning I went down to kragen to get a couple fuses for my TCS and ABS cause I wanted them to work again.I'm running 26" tires front and back now instead of the 28" slicks and 26" skinnies which messed everything up..
Put the fuses in (not saying its related prob coincidence), fired the car up and now it idles great. Right at 1100, smooth acceleration, no abnormal bucking / surging. It's like a dream. No more p0103, either.
I completely ruled out anything fueling. I already replaced the whole fuel assembly in the rear due to another problem, and i'm running a hotwire kit.
I'm assuming something is gonna happen again and the car is gonna go back to driving shitty. Anyone have any ideas as to what would cause this? I thought maybe a vacuum leak, but that wouldn't just "disappear."
help
A few days ago I took my car to my tuner to get the idle set with the new accufab tb for the TPS and IAT. Everything was dialed in pretty good... car ran ok, also did some fuel trims, basically a small street tune to break in the motor and clutch before hitting the dyno.
All of a sudden it started bucking and surging really bad at any RPM under about 2500. Way more then you would expect even for a mid 260's cam, and I started throwing a p0103 code (map reading high). Car also wouldn't find idle, would constantly try to die.
Did it for about two days. Now, about 150miles later, this morning I went down to kragen to get a couple fuses for my TCS and ABS cause I wanted them to work again.I'm running 26" tires front and back now instead of the 28" slicks and 26" skinnies which messed everything up..
Put the fuses in (not saying its related prob coincidence), fired the car up and now it idles great. Right at 1100, smooth acceleration, no abnormal bucking / surging. It's like a dream. No more p0103, either.
I completely ruled out anything fueling. I already replaced the whole fuel assembly in the rear due to another problem, and i'm running a hotwire kit.
I'm assuming something is gonna happen again and the car is gonna go back to driving shitty. Anyone have any ideas as to what would cause this? I thought maybe a vacuum leak, but that wouldn't just "disappear."
help
Thread Starter
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From: Bay area, ca.
nobody huh....
Today it acted up bad again... going up an incline on the freeway and the car just started cutting out.
When it happens, the car will not rev, no matter how hard I press the gas, then all of a sudden it will kick in, and BAM, power and it gives me whiplash. Fuel pressure looks good even with it messed up.
Problem only happens under load, car will free rev whenever I want. Now i'm not throwing MAP codes, but I'm throwing TPS codes. But I just got a street tune and all seemed well for the TPS when we set the voltage..
Also have the "Service Vehicle" (not SES) light on all the time, but it's been on since as long as I can remember.
ANNNYONE?
Today it acted up bad again... going up an incline on the freeway and the car just started cutting out.
When it happens, the car will not rev, no matter how hard I press the gas, then all of a sudden it will kick in, and BAM, power and it gives me whiplash. Fuel pressure looks good even with it messed up.
Problem only happens under load, car will free rev whenever I want. Now i'm not throwing MAP codes, but I'm throwing TPS codes. But I just got a street tune and all seemed well for the TPS when we set the voltage..
Also have the "Service Vehicle" (not SES) light on all the time, but it's been on since as long as I can remember.
ANNNYONE?
Last edited by jermzz; Oct 19, 2008 at 07:07 PM.
Have your tune double checked.
Double check ALL of your wiring. If you have an intermittent problem it could be a loose or bad connector.
Next if I where in your shoes I would do a double check on the ignition and sensors. If you have easy access to an O-scope throw it on your coils to confirm proper operation. I would then start looking at sensors. Basically start ruling out things it could be. Look at your inputs and outputs and never assume. Usually if it happens under load it points towards an ignition issue but with these systems it's rare, so confirm it. Even the wires and plugs.
Good Luck.
Double check ALL of your wiring. If you have an intermittent problem it could be a loose or bad connector.
Next if I where in your shoes I would do a double check on the ignition and sensors. If you have easy access to an O-scope throw it on your coils to confirm proper operation. I would then start looking at sensors. Basically start ruling out things it could be. Look at your inputs and outputs and never assume. Usually if it happens under load it points towards an ignition issue but with these systems it's rare, so confirm it. Even the wires and plugs.
Good Luck.
Thread Starter
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From: Bay area, ca.
problem fixed.
ended up being the TCS / cruise control unit malfunctioning.
just took all the abs fuses, tcs fuse and disconnected the unit from the plug and the car drives normal now. Gotta get a new one.
ended up being the TCS / cruise control unit malfunctioning.
just took all the abs fuses, tcs fuse and disconnected the unit from the plug and the car drives normal now. Gotta get a new one.
