Help with missfire problem
04-06-2012, 04:49 PM
#1
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Help with missfire problem Im not sure if this is the correct place to post this but I will give it a shot.
I have a 98 Trans Am with 94,000 miles the mods are in my sig.
The problem I am having is when I stop at a red light the car starts to missfire and the oil pressure gauge starts radically changing from a normal psi to a lower one. And ocassionally shuts off.
I took it to a shop by me and they checked the
ignition coils all are working properly
spark plugs all gapped correctly
fuel pump tested fine
did a leakdown test and it tested great, good compression in all cylinders.
tightened the springs only one was barely loose
Im sure im leaving something out Iwill have to check the receipt on what else they checked.
But after many man hours are $1,100 later it still does it, not as bad but def. noticable and really annoying.
Do any of you fellow members have any idea as to what else it could be?
I also do have a full dyno tune, and the shop that did the tune did this work on the car too.
I have a 98 Trans Am with 94,000 miles the mods are in my sig.
The problem I am having is when I stop at a red light the car starts to missfire and the oil pressure gauge starts radically changing from a normal psi to a lower one. And ocassionally shuts off.
I took it to a shop by me and they checked the
ignition coils all are working properly
spark plugs all gapped correctly
fuel pump tested fine
did a leakdown test and it tested great, good compression in all cylinders.
tightened the springs only one was barely loose
Im sure im leaving something out Iwill have to check the receipt on what else they checked.
But after many man hours are $1,100 later it still does it, not as bad but def. noticable and really annoying.
Do any of you fellow members have any idea as to what else it could be?
I also do have a full dyno tune, and the shop that did the tune did this work on the car too.
04-06-2012, 05:16 PM
#2
Get it scanned and see what the 02 sensors are doing.......switching properly or not.
Also, you might need a new "Coolant Temp Sensor". In the 98's, which I have, when they start to fail the engine will start to run like **** and ultimately it will make the engine stall out when idling.
Make sure none of the spark plug wires are touching ANY metal all all.......
Thats a big bill dude....you should have come here first.
.
Also, you might need a new "Coolant Temp Sensor". In the 98's, which I have, when they start to fail the engine will start to run like **** and ultimately it will make the engine stall out when idling.
Make sure none of the spark plug wires are touching ANY metal all all.......
Thats a big bill dude....you should have come here first.
.
04-06-2012, 05:51 PM
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I have 2 new O2 sensors in the LTs, and that helped a little bit, the downstream O2's are tuned out.
It isn't throwing any codes as of right now, which is why I am so confused.
I will check the spark plug wires, I have the MSD ones and I bought those 2 or 3 years ago.
I now know I should have come here first but stupid me thinking an LS1 specific shop here in MI who did a lot of work on my car would have been able to figure it out. and had it for roughly 3 or 4 days.
It isn't throwing any codes as of right now, which is why I am so confused.
I will check the spark plug wires, I have the MSD ones and I bought those 2 or 3 years ago.
I now know I should have come here first but stupid me thinking an LS1 specific shop here in MI who did a lot of work on my car would have been able to figure it out. and had it for roughly 3 or 4 days.
04-08-2012, 10:43 AM
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How would I go about cchecking the fuel trims?
I also wonder if there could be a short somewhere in the nitrous wiring? Is there anywhere specifically where a wiring problem from the nitrous could cause various cylinders to miss?
I also wonder if there could be a short somewhere in the nitrous wiring? Is there anywhere specifically where a wiring problem from the nitrous could cause various cylinders to miss?