Dead Miss at Cold start, crank shaft sensor, P0507
January 1st, 2013, 10:10 PM
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Dead Miss at Cold start, crank shaft sensor, P0507
Hi guys. First post here, and i've got a few different questions.
2002 Chevy S10 with 115K on it. Transmission is in good shape, and engine runs like a sewing machine after it's warmed up, but i do have a few funny issues.
The big one, is a dead miss when cold. I'm thinking it's either spark plugs, or crankshaft position sensor (only thinking that because i'm getting a code relating to that). I'm also seeing the tach kinda... "spike" to 6K under hard acceleration (and my Ultra Gauge is saying 11K RPM (!) when this happens), and i can feel a loss of power until it goes into the next gear and RPMs fall below 4K. From what i can find, this is classic of a crankshaft sensor, but i'm curious if there's anything else that may cause this. Going to check the plugs and compression Thursday.
Another weird thing is a P0507 code. Idle Air Control revolutions higher than expected. This came up after we cleaned the throttle body and replaced the air filter. Went ahead and replaced the IAC valve, and while i'm not getting the code as much, i do still get it every now and then. I've checked for vacuum leaks, and i can't find any. I'm wondering if maybe the dead miss at idle is causing the truck to try to give the engine more air, and then when the miss stops (around 120f) it spikes and confuses the ECU?
2002 Chevy S10 with 115K on it. Transmission is in good shape, and engine runs like a sewing machine after it's warmed up, but i do have a few funny issues.
The big one, is a dead miss when cold. I'm thinking it's either spark plugs, or crankshaft position sensor (only thinking that because i'm getting a code relating to that). I'm also seeing the tach kinda... "spike" to 6K under hard acceleration (and my Ultra Gauge is saying 11K RPM (!) when this happens), and i can feel a loss of power until it goes into the next gear and RPMs fall below 4K. From what i can find, this is classic of a crankshaft sensor, but i'm curious if there's anything else that may cause this. Going to check the plugs and compression Thursday.
Another weird thing is a P0507 code. Idle Air Control revolutions higher than expected. This came up after we cleaned the throttle body and replaced the air filter. Went ahead and replaced the IAC valve, and while i'm not getting the code as much, i do still get it every now and then. I've checked for vacuum leaks, and i can't find any. I'm wondering if maybe the dead miss at idle is causing the truck to try to give the engine more air, and then when the miss stops (around 120f) it spikes and confuses the ECU?
January 1st, 2013, 10:46 PM
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Not sure if they're original or not. I'm a second (or third) hand owner of this truck. Been fixing lots of little issues... Got it for $1200, and i have $500 in it so far for parts and stuff, so i'm happy so far. Down from 12 DTCs to 1, or sometimes 2. How would i know if they're original? They all look fairly new, as does the distributor cap.
January 2nd, 2013, 10:44 PM
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So, finished the compression test. Showed ~120PSI on all cylinders except for the one closest to the cabin on the passenger side. That guy was just over 90, so i guess that's the cause of my miss at cold start. Does anyone know of any possible easy fixes for that? i've read that carb cleaner down the intake, or seafoam down the break booster vacuum line can sometimes clean out gunk around the valves... Is this worth trying?
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