That is normal, don't worry about it.
This is a discussion on WRX not smooth from startup within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; Hi, I have a WRX wagon 1996, I have noticed over the past few days when starting after it has ...
I have a WRX wagon 1996, I have noticed over the past few days when starting after it has been parked overnight or if it has been left for a couple of hours when I get in a start driving it appears to 'miss' slightly, it is fine if I accelerate moderately but if I am driving gently it has a subtle jerk or lack of smoothness. When it warms up it is absolutely fine and goes like a bullet. I have replaced the fuel pump due to failure a few months ago so that is not the issue, it has been serviced regularly but I have not, as yet changed the plugs, building up the enthusiasm for those!
Could this be an engine management problem or one of the sensors, it feels as if it is running slightly weak when cold, just like a car would with a carburetor/choke not working properly.
That is normal, don't worry about it.
If its about time to change the spark plugs out then you might not feel it when you change them out. My ride was feeling real weak as well. Bad loss of power, but I chnaged my plugs out and It seamed like the car I was driving when I first bought it. It was sweet. The plugs aren't that hard, you do have to get up some enthusiasm like you said cause its always a pain in the ass to get to them. So good luck, Im sure you'll feel a difference one you get those done.
Did this literally just start one day out of nowhere, i.e. the problem wasn't there at all the day before, then it was? If so, I'd start with the simplest thing: Did you get a bad tank of gas? If it did start all at once and it's not the gas, then I'd start looking at sensors. Do you have an OBDII reader? (actually is a '96 an OBD or OBDII car? hmmm...)
Past Subies - '11 STI Limited stage 1+ and '04 STi stage 2+
'13 Wrangler Rubicon - custom front bumper w/12k lb winch & off-road lights, skid plates, diff guards, etc.
'04 Porsche 911 Turbo GT2 clone 600 HP/TQ
'77 F-150 heavily modded for off-roading
Yea the gas might be it too. I just heard on the news that if you live in the Seattle or somewhere up there that they found water in the gas and cars were breaking down. You might want to look up where it was exactly.
Scragger...there are some threads on here about general maintenance and tuneup. I would suggest checking the easy things first:
-Idle Air Control Valve
-Boost leaks/vacuum leaks
-Spark plugs/plug wires. Not sure if the 96 models have coil over plug ignition or if they have centrally mounted coilpacks...if they do have plug wires (big long thick wires that plug into a central coilpack and then into the spark plug) you might take a look and double check they are all snug. If you have coil over plug (like modern WRX's do) then just make sure all the coilpacks are properly attached and all electrical connections are secure.
Thanks Timdog, I too stopped dead when I read ROAR's reply, it is most definitely not normal.
I have the coil packs over plug I believe, fed by thinnish wires, they obscure access to the plug. I'm told that a little care is needed when removing them.
I'll check what you advised, I was wondering if it could be the MAF or idle valve, it just seems odd that it runs fine if driven moderate to hard when cold but 'jerks' when driven gently from cold.
Okay, yeah sounds like you have coil over plug.
It could possibly be a normal subaru thing, but you make it sound like it's more aggravated then the normal "cold motor blues" that subies get. I did a at Roar's reply because it was his first post...ever, lol. If a basic tuneup/inspection doesn't find a problem, I would try to burn out the tank of gas you're running and put some name brand gas in there. Not sure what you normally run, but sometimes a lousy tank of petrol will screw your whole day up.