Car spudders and stalls when I give it gas ...
05-07-2006, 05:05 PM
#1
Car spudders and stalls when I give it gas ... Stock 99 LS1 ... car starts up and cold idles fine, revs fine, everything seems good. Once the temp gauge hits about 130ish, the idle drops significantly (600 or so rpms), and the car starts to run very rough. If you give it gas, it spudders and will stall if you hold the TB blade open for 2-3 seconds.
I have taken the intake off, and replaced it with a different one ... checked out all the vacuum hoses to see if there was a leak (was none)... and even replaced the injectors with a new set.
It seems to me, that a sensor that the computer doesn't pay attention to while the car is cold (like the o2's) may be bad, which would cause it to idle crappy when the PCM switches into a warm idle mode. I don't want to just go replacing all my sensors w/o any real idea however.
I'm pretty much stumped. Any suggestions?
I have taken the intake off, and replaced it with a different one ... checked out all the vacuum hoses to see if there was a leak (was none)... and even replaced the injectors with a new set.
It seems to me, that a sensor that the computer doesn't pay attention to while the car is cold (like the o2's) may be bad, which would cause it to idle crappy when the PCM switches into a warm idle mode. I don't want to just go replacing all my sensors w/o any real idea however.
I'm pretty much stumped. Any suggestions?
05-08-2006, 02:21 AM
#3
Originally Posted by Kounsy
your coolant temp sensor could be bad to make it run rich and make it stall and make the car want to die. Is your ses light on.
05-08-2006, 05:30 PM
#5
If I disconnect the MAF only it doesn't seem to help out much ... if I disconnect the MAF and intake temp sensor, it seems to make the problem slightly better. It will hold a higher idle, and take a little bit more throttle then it would before .... by no means does it run perfect however.
It was burning coolant recently (head gaskets leaking), so I am thinking this might have possible destroyed the 02 sensors? Would that cause these symptoms?
It was burning coolant recently (head gaskets leaking), so I am thinking this might have possible destroyed the 02 sensors? Would that cause these symptoms?
05-08-2006, 05:43 PM
#6
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Hey Mike I woould unscrew the O2's and see what they look like,Hope you figure it out man and get that badboy back on the road kicken some butt.Just some more ideas try some elses Maf see if that helps.Did you look at the spark plugs are they fouled out maybe?
Dave
Dave
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05-09-2006, 11:42 PM
#8
Originally Posted by INTENESS
Hey Mike I woould unscrew the O2's and see what they look like,Hope you figure it out man and get that badboy back on the road kicken some butt.Just some more ideas try some elses Maf see if that helps.Did you look at the spark plugs are they fouled out maybe?
Dave
Dave
Yeah I figured that tomorrow or wednesday I would probably take my o2's out and visually inspect them and see if they looked screwed up. The MAF is also still on my list, so maybe if that doesn't work I'll see if I can find someone in the area that wouldn't mind letting me borrow their MAF for a few minutes. The problem is I changed so many things putting this thing back to stock, it's been difficult to try to narrow down what it could be. Seems like I'm getting there though.
a coil could also break down, let your car act up until that damn ses light comes on.
05-29-2006, 09:47 PM
#9
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having the same prob too. My trims go to -15 to -20. It will not die if I let off and just let it idle but giving it gas floods it and will back fire on occasion. No SES light either. This started when I put new header gaskets on. I thought a plug went bad so replaced them all but didnt help.
05-31-2006, 03:24 PM
#11
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Grounding Straps? You refereing to one in particular? btw, I replaced the TPS yesterday and one of the new spark plugs that was showing the highest misfire( at times 60+) and it's still studdering/dying. Using EFIlive and nothing is looking out of the ordinary except the misfires when it starts acting goofy. I guess I need to find out what the normal operating voltages are for everything to start rulling areas out. So now I have to switch some wires to rule them out.
I have looked over the wires really closely but the o2 wiring has to be causing all this because it is only doing this when the o2s are being used. Guess to test this, I could disable the open loop and only use closed loop to see if it still does it.
I have looked over the wires really closely but the o2 wiring has to be causing all this because it is only doing this when the o2s are being used. Guess to test this, I could disable the open loop and only use closed loop to see if it still does it.
Last edited by ttujason02; 05-31-2006 at 03:35 PM. Reason: add more detail
05-31-2006, 07:23 PM
#13
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hehe. nope, made that $500 mistake when I first got the car. I have narrowed it down to cylinder #2. either wire or coil pack. I pulled the valve cover but it looked fine. Hopefully just a bad coil pack.
05-31-2006, 11:06 PM
#14
Originally Posted by ttujason02
Grounding Straps? You refereing to one in particular? btw, I replaced the TPS yesterday and one of the new spark plugs that was showing the highest misfire( at times 60+) and it's still studdering/dying. Using EFIlive and nothing is looking out of the ordinary except the misfires when it starts acting goofy. I guess I need to find out what the normal operating voltages are for everything to start rulling areas out. So now I have to switch some wires to rule them out.
I have looked over the wires really closely but the o2 wiring has to be causing all this because it is only doing this when the o2s are being used. Guess to test this, I could disable the open loop and only use closed loop to see if it still does it.
I have looked over the wires really closely but the o2 wiring has to be causing all this because it is only doing this when the o2s are being used. Guess to test this, I could disable the open loop and only use closed loop to see if it still does it.
The grounding strap is the one that goes to the front of the drivers side head, and travels down to the frame near the headlight. That was loose on my car, and apparently causing one of the sensors to work incorrectly ... ontop of the O2 sensor issue.
07-15-2006, 08:13 PM
#16
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I had the same problem and got a tune from RPM. It ran good for about a month and started doing this again. It just sputters and chops like **** for the first couple of minutes and then runs fine.
07-15-2006, 10:41 PM
#17
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This was happening to my LT1 daily beater recently. When it got up to operating temp it would do exactly what yours does.
It turns out that the O2 sensors are only in control when the coolant gets up to operating temp, then the bad O2's were f'ing up everything.
Simply unhook the connection to (1) of your front O2's. It will force the computer to stay in open loop when the car gets up to operating temp, the O2's will have no control. If the car runs perfectly after it gets up to temp then you know that you should change both of the front O2's.
I did that and my LT1 ran like a champ!!! After that I went to Auto Zone and bought 2 new O2's and replaced them and it's solved.
Summary: unplug one of your O2's and drive your car around to see if the stumbling stops... I'll bet $50 that you find that to be the case.
Let us know what happens.
~Joshua
It turns out that the O2 sensors are only in control when the coolant gets up to operating temp, then the bad O2's were f'ing up everything.
Simply unhook the connection to (1) of your front O2's. It will force the computer to stay in open loop when the car gets up to operating temp, the O2's will have no control. If the car runs perfectly after it gets up to temp then you know that you should change both of the front O2's.
I did that and my LT1 ran like a champ!!!
After that I went to Auto Zone and bought 2 new O2's and replaced them and it's solved.Summary: unplug one of your O2's and drive your car around to see if the stumbling stops... I'll bet $50 that you find that to be the case.
Let us know what happens.
~Joshua
07-16-2006, 01:55 AM
#18
Joshua, thanks for the chime. This post was from awhile ago though, and I've got a new car now. lol. Just for anyone who may have this identical problem, I will give you an update as to what the story was.
It turned out I had quite a few problems, which was the reason it was so hard to diagnose.
1. The Drivers side o2 sensor was bad.
2. The TPS Sensor was f'd.
3. The fuel part of my tune was slightly off.
Multiple problems suck.
It turned out I had quite a few problems, which was the reason it was so hard to diagnose.
1. The Drivers side o2 sensor was bad.
2. The TPS Sensor was f'd.
3. The fuel part of my tune was slightly off.
Multiple problems suck.
