Intermittent Check Engine Light and Rough Idle

[e46s54dr]

My car has been acting up on occassion but it isn't too bad. I'd like to get her to run perfectly if I can. Any help would be deeply appreciated!

1st Problem: Engine runs a little rough with sporatic idle on cold start ups. Once the engine warms up, all symptoms dissappear. I recently replaced the coolant tempeture sensor and it felt a smidge smoother, but my CEL is lit at idle

2nd Problem: When I'm cruising on the freeway or any road where I'm at a constant speed/rpm, my CEL will be on. As soon as I give her more gas or let off on the throttle the CEL turns off.

My guess is that the two problems are connected in some way but I'm not 100 percent positive.

P.S. Will a small vacuum leak from the idle control valve boot cause the said symptoms?

[ak-]

I have the same problem. I'm just living with it for now.

[e46s54dr]

Yeah, it really doesn't bug me too much but it wouldn't hurt to see if anyone had the same problem and have a solution.

[Desaevious]

Same as you two, subscribed, lol. I popped in a new thermostat and flushed the coolant to see if that was the cause and since I had no idea when the last thermostat was installed so it was a simple task. I'm thinking it might be some type of air intake issue?

[e46s54dr]

Same as you two, subscribed, lol. I popped in a new thermostat and flushed the coolant to see if that was the cause and since I had no idea when the last thermostat was installed so it was a simple task. I'm thinking it might be some type of air intake issue?

When I had my car smogged, it passed with flying colors. I asked the mechanic what he thought about my symptoms and he said that it was most likely a vacuum leak somewhere. It just kinda sucks that the cel doesn't stay on so I can extract the code to give me some sense of direction.

[Desaevious]

When I had my car smogged, it passed with flying colors. I asked the mechanic what he thought about my symptoms and he said that it was most likely a vacuum leak somewhere. It just kinda sucks that the cel doesn't stay on so I can extract the code to give me some sense of direction.

Yeah the sniffer has my emissions as being good too. So then vaccum leak maybe? Issue with the idle control valve?

[Danny]

O2 sensor.

[e46s54dr]

It's not the o2 sensor in my case. Mine is brand new and I have an oem low mileage cat.

[e46s54dr]

Yeah the sniffer has my emissions as being good too. So then vaccum leak maybe? Issue with the idle control valve?

I plan on swapping out my icv and resealing the known leak and any other vacuum leaks I can find sometime this week. I'll update if I see any results.

[Desaevious]

I plan on swapping out my icv and resealing the known leak and any other vacuum leaks I can find sometime this week. I'll update if I see any results.

Cool. Its something I'd like to monkey around with but its not a "need to do" thing as you know. With it being my only car, embarking on even the smallest of projects on what I need to drive to work and school aren't gonna be done if they won't promise results. Let us know man!

[Danny]

What motor is it?

[ak-]

I replaced the icv, and it helped a shit ton. Not 100% still though.
Before the icv though, I would have to be and a constant heel-toe at stop lights to prevent my car from shutting off most of the time.

[e46s54dr]

What motor is it?

Oops, totally forgot to mention it was a m20b25.

[N2MYE30]

This kinda happened to me this weekend.

1) I didnt drive the car for 8 days
2) then took a 30 mile highway drive on a near empty tank but knew I could get to my destination
3) After ~5 miles the CEL light comes on but goes off after I let ease off the gas
4) ~25 miles into the trip the light stays on no matter what
5) I pull into a gas station looking for my stomp test instructions but in another car (one of the negatives of having too many cars)
6) I filled up the car and the CEL was still on and drove away since I had no other choice and the car still ran normal...a bit of a rough idle but not bad.
7) 2 miles down the road the CEL goes off
8 ) I got to my destination and drove back 30 miles with no CEL light on.

Bad gas? I dunno.
O2 Sensor? maybe but the sensor could be detecting something legit...but what?

[e46s54dr]

Definitely very odd. I wonder if my fuel pump might be the culprit. It's just a shot in the dark but im going to change it out for a new one since it's never been changed to the best oh knowledge. I'm glad that I'm not the only one expiriencing these crazy symptoms. I'll work ony car this weekend and let you guys know how things go.

This kinda happened to me this weekend.

1) I didnt drive the car for 8 days
2) then took a 30 mile highway drive on a near empty tank but knew I could get to my destination
3) After ~5 miles the CEL light comes on but goes off after I let ease off the gas
4) ~25 miles into the trip the light stays on no matter what
5) I pull into a gas station looking for my stomp test instructions but in another car (one of the negatives of having too many cars)
6) I filled up the car and the CEL was still on and drove away since I had no other choice and the car still ran normal...a bit of a rough idle but not bad.
7) 2 miles down the road the CEL goes off
8 ) I got to my destination and drove back 30 miles with no CEL light on.

Bad gas? I dunno.
O2 Sensor? maybe but the sensor could be detecting something legit...but what?