mtn
MegaDork
11/21/12 9:07 a.m.
Yesterday I drove the Miata (DD) to and from work, no problems. Then I went to the girlfriends place, and for the first 10 seconds it was running really, really rough (still sitting in garage). After that it was fine, but the check engine light came on. Drove to the girlfriends (~.5 mile), no issues, drove normal. Drove from her place to the AdvanPepZone, pulled a P0300 (Random Misfire). Still drove normal on the way there. I stupidly didn't have them clear it and see if it would come back. Drove normal on the way in to work this morning as well.
I'm guessing that it is going to be plugs+wires (I'll do this anyways since I have no idea the last time it was done) or coils. Timing belt was changed about 20k ago. The last time I filled up was at a Citgo or Shell, I can't remember, but I put in a half tank of BP just in case the culprit was bad gas.
Now, the question at hand, would you guys drive on it for a 120 mile trip that I was planning on making today? The big thing I'm worried about and inexperienced and dumb enough not to know, is there anything catastrophic that could happen from me driving on it?
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Yes, I would drive it on the trip if all things seem normal.
I get that every once in a while - minus the CEL. It clears its throat and is then fine again for months.
What year's the car? On a 1999-00, that can mean the coils are going out - which will take out the cat with raw fuel due to misfires.
It could have just been a bad start due to old plugs and a cold motor. But until you've determined it was a one-time problem, I'd rather see you take a different car on your trip if you have one available. You'll probably be fine as long as the car is driving normally, but just in case.
I'd drive it. The CEL on my work van doesn't work, but it has started to spark knock burning 87 gas. I just pulled the codes on it. There were 6 of them. Lean bank 1 sensors 1 & 2, lean bank 2 sensors 1 & 2, EGR low flow, enrichment at maximum range. My guess is vacuum leak. I put 300 miles on it yesterday and it will be Monday before I get a chance to look at it.
mtn
MegaDork
11/21/12 10:04 a.m.
Keith Tanner wrote:
What year's the car? On a 1999-00, that can mean the coils are going out - which will take out the cat with raw fuel due to misfires.
It could have just been a bad start due to old plugs and a cold motor. But until you've determined it was a one-time problem, I'd rather see you take a different car on your trip if you have one available. You'll probably be fine as long as the car is driving normally, but just in case.
It is a 1999. Car is driving normally, but my other option is the train which would cost me over $75 and take 4 hours longer 
I'm gonna go ahead and risk it. If I take out the cat, then I can't say you didn't warn me.
Most other situations I'm able to go without my car for weeks on end, but not right before Thanksgiving
Check the short plug wire closest to the firewall. Sometimes they contract and work loose in cold weather.
mtn wrote:
Keith Tanner wrote:
What year's the car? On a 1999-00, that can mean the coils are going out - which will take out the cat with raw fuel due to misfires.
It could have just been a bad start due to old plugs and a cold motor. But until you've determined it was a one-time problem, I'd rather see you take a different car on your trip if you have one available. You'll probably be fine as long as the car is driving normally, but just in case.
It is a 1999. Car is driving normally, but my other option is the train which would cost me over $75 and take 4 hours longer
I'm gonna go ahead and risk it. If I take out the cat, then I can't say you didn't warn me.
Most other situations I'm able to go without my car for weeks on end, but not right before Thanksgiving
Yeah, bad timing. Let's hope it was a one-time problem! Throwing in a set of new plugs wouldn't be a terrible investment if they are of unknown vintage. Just in case.
