Check Engine Light Flashing - Noticeable Vibration

**coolwhipdefuser** · 04-23-2007, 07:55 PM

When I was driving home tonight, I was getting ready to get on the interstate (65mph) and was on the ramp, and I turned my AC off because I felt I didn't need it anymore, and I didn't want it pulling on my engine when I was accelerating. So I start to get on the interstate, and I hit around 50-55mph and my engine downshifts to give me some extra power to get up to 70mph, and I notice that my car suddenly looses some power and my check engine light starts flashing. My car is still accelerating, but I lost some of my power. It flashes for maybe about 5-10 seconds and then stays lit.

I pull over, and pop the hood and check and see if a hose has come loose or something (I had no idea what was wrong) but to no avail, engine bay seems perfectly fine, so I make sure the gas cap is on tight and restart the car, and the CEL is still lit. But I have to get home, so I get back on the interstate to drive the extra 5 miles or so to get home, and I get up to about 60mph and I notice a significant vibration that shakes the whole car when I try to accelerate any higher. I slow a bit and make sure I'm in the right lane, and then I try to accelerate again, but when it shifts into whatever gear it was in (I'm not sure which, felt like 4th) it vibrated again. So I drove home very carefully and came in here to write this.

I don't know if anyone will see this thread tonight, but I plan to take the car by my indie mechanic tomorrow morning and see if he can check and see if the car is throwing codes, or else he may know what the problem is by me describing it. Anyone know what may be wrong/have happened with my car?

**JRL** · 04-24-2007, 05:39 AM

MAF sensor. Clogged catalytic converter. A real bad 02 sensor, the list can be endless.

**coolwhipdefuser** · 04-24-2007, 06:25 AM

Ok, thanks for those options JRL, I'm going to be taking it in in a little while, I'll give you guys updates when I found out what's wrong.

**coolwhipdefuser** · 04-24-2007, 03:01 PM

He ran the codes and said I have a plug misfire. I think I'm taking it in again tomorrow, since he couldn't do anything with it today. He said it may be from a bad batch of gas, and he highly recommended me running high octane fuel in it. I can't really afford that kind of gas, but we'll see what he finds when he pulls the plugs tomorrow, and he'll be able to give me a better idea of what is causing the misfire.

**JRL** · 04-24-2007, 04:18 PM

Originally Posted by coolwhipdefuser

He ran the codes and said I have a plug misfire. I think I'm taking it in again tomorrow, since he couldn't do anything with it today. He said it may be from a bad batch of gas, and he highly recommended me running high octane fuel in it. I can't really afford that kind of gas, but we'll see what he finds when he pulls the plugs tomorrow, and he'll be able to give me a better idea of what is causing the misfire.

Tuned up recently?

(within the past 30K miles)
A good set of plugs, wires and a rotor will probably do wonders... as will better gas. I hope you're not running 87, 89 is fine

**coolwhipdefuser** · 04-24-2007, 04:22 PM

Yeah, I run 89 in my car, and have since I got it. I know it has been tuned up within the past 30k, but I'll have to check my records to see exactly how long ago it was. He'll check the plugs tomorrow, he was the one who did it anyway. I'm hoping it's just a bad plug or something, because the car is getting difficult to drive.

**mrscullini** · 04-25-2007, 09:12 AM

Originally Posted by coolwhipdefuser

He ran the codes and said I have a plug misfire. I think I'm taking it in again tomorrow, since he couldn't do anything with it today. He said it may be from a bad batch of gas, and he highly recommended me running high octane fuel in it. I can't really afford that kind of gas, but we'll see what he finds when he pulls the plugs tomorrow, and he'll be able to give me a better idea of what is causing the misfire.

with regard to high octane fuel, how do you drive? do you drive very aggressively or are you gentle on the accelerator? if you drive aggressively then you should definitely use high octane fuel. if you are gentle on the accelerator then low grade fuel is fine and should not cause the problem you are experiencing.

all modern cars are equipped with knock sensors. these devices detect "knock" caused by pre-ignition of the fuel. if a "knock" is detected, the timing is automatically retarded to minimize or eliminate the pre-ignition condition.

let us know what your guy says. post which code(s) were pulled and if he finds a faulty plug, let us know which plug.

**coolwhipdefuser** · 04-25-2007, 11:19 AM

Ok, well, I just got an update this afternoon. No faulty plug. I've got a burned out valve on the exhaust side of the #2 cylinder. Not sure how much it will cost yet, but he estimates a couple day job. Seems like a long time to me, but then again, I don't know how long things like this take.

**mrscullini** · 04-25-2007, 12:11 PM

Originally Posted by coolwhipdefuser

Ok, well, I just got an update this afternoon. No faulty plug. I've got a burned out valve on the exhaust side of the #2 cylinder. Not sure how much it will cost yet, but he estimates a couple day job. Seems like a long time to me, but then again, I don't know how long things like this take.

bummer man.

2 days doesn't seem bad. he will have to pull the head. you will definitely want to replace the timing belt/tensioner/idler while he is in there. the belt will definitely have to come off to pull the head. you may want to consider a valve job while the head is off, if the seats are in marginal or poor condition.

i'm sure there are some other items to consider since he is digging into it. if you really trust this guy i would ask his opinion on other items to replace since the head is off. just don't let him get too opportunistic.

**coolwhipdefuser** · 04-25-2007, 02:23 PM

I just got another update from him. He now says about five working days, because he can't do all the work himself, he has to take it by a machine shop to have some stuff ground down. Also, my timing belt was replaced last week.

And thankfully we do trust this guy, he's been working on our Volvos since we moved here (about 18 years ago) and we've bought a total of five used Volvos from him throughout the years.