My wife's 2003 trailblazer has been running rough occasionally, like once every 2 or 3 weeks for only about a minute. It feels like a misfire, but no codes, and no flashing SES light. I was driving it around today and it started running rough again, so I kept driving it and it stayed rough for about 12 miles; but still no codes...... after getting frustrated with no code I stomped on the gas, and the roughness/misfire slowly went away. Now it's running smooth again. Anyone have any ideas as to what can cause this? thanks.
'03 occasionally runs rough
- Thread starter signalnc
- Start date
As we always say, clean the throttle body. More than likely it is gummed up with carbon and a simple cleaning would bring it back to life. I clean mine 2 times a year, once in the spring and again in the fall so I don't have to worry about it gumming up and breaking like my OEM throttle body did.
It could also be something simple like maybe the fuel filter is old and very dirty so it's starving your engine for gas.
It could also be something simple like maybe the fuel filter is old and very dirty so it's starving your engine for gas.
When you cleaned it, how dirty was it? Was it a thin coating or was it really thick and hard to get off the surface? If it was thick, you may want to go through and reset the PCM with it cleaned up and see if that helps. Also, if you disconnected the battery or did reset the PCM, I noticed on my truck that usually for the first week after, the truck either wants to stall or succeeds in stalling when at a stop so don't be too alarmed with that.
The throttle body wasn't too bad. I did do a relearn after I cleaned it. The rough/misfire was happening before I cleaned it .
IllogicTC
Member
- Dec 30, 2013
- 3,452
I'd think fuel filter too. How many miles, and service history on the filter? If you have live data capability on your reader, you can monitor the fuel rates. If it's consistently in the double digits, it's definitely not getting enough fuel, but it has to max out I believe (25%) before it'll give a P0171 code.
thanks for the tip on the live data fuel rate. I will read it tomorrow. I just got dash command, and it has fuel rate capability.
The filter is due anyway. I think I've got 25k on it.
The filter is due anyway. I think I've got 25k on it.
