'03 P5 starts slow, eventually takes off, rough idle, engine light?

redcalimp5

Member
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'03 P5
A couple of days ago my engine light came on. I noticed soon after that that the engine started to sputter a little, like I might have a vacuum leak or something. Everytime I took off from a complete stop, it seemed like I didn't have any engine power until it got up to about 3500RPM's, and then it would take off like it normally does. So I take it in to get looked at, the guy puts the ODII on it, tells me it reads "random misfire". I've never changed the spark plugs(94,500mi), and the head gasket has always leaked....but not bad enough to notice significant oil loss. It was evident around the valve cover, though, that it leaked.

So the mechanic recommends new spark plugs, all new plug wires, and a head gasket replacement. The day after they did this work she ran fine, the 2nd day after, the engine light came on again, and when I'd pull up to make a stop at a light, the engine would sputter bad, and then the engine would die. I was able to restart it quickly, and it took off slow for a couple seconds, and then took off like normal.

I take it back into the same place, they have it all day(yesterday). I call them after 4 hours, and the manager told me on the phone that they were still trying to figure out what was wrong with it. Two more hours pass, and I call them again. The same guy tells me that the large hose that connects the air filter housing to the engine had a 2 inch tear in it. They replaced it, and it ran fine....for a couple of hours. Later last night, it started doing the same things again....slow start from a stop, and then it takes off, and there is still random engine sputtering, although it's not enough now to where the engine dies like before. And the engine light is STILL on.

At this point, I've pretty much lost faith in this shop's ability to resolve whatever issue my car is happening. I've dropped $500 in 3 days with them, and I'm still having the same issues. They obviously aren't equipped to handle the type of issue that I'm experiencing, and I'm sure they'll just keep "guessing" and replacing parts until they eventually get it right, if I were to bring it back to them.

I'll be calling my local Mazda dealership/service center in a little bit, so see what it will cost to get a diagnostic done, and hopefully find out FOR REAL what's going on with my engine. I hate going to the dealership, but I don't feel I can trust anyone else local in town.
 
They didn't replace the head gasket if you've only been charged $500. That job alone is at least $750-800. Are you sure they didn't just replace the valve cover gasket?
 
Ok. Try harder guys. Its the timing, the intake side is off by 2 or 3 teeth. Replace the belt and tensioner and make sure the timing marks line up horizontally
 
Ok. Try harder guys. Its the timing, the intake side is off by 2 or 3 teeth. Replace the belt and tensioner and make sure the timing marks line up horizontally

Not an EGR valve? That would have been my guess to since it fixed my rough idle. I installed the Canadian version, not as bad as everybody says.
I'm kind of a new guy but what would cause the intake side to be off by 2-3 teeth?
 
$500 in three days is not much for what your describing. It was probably the vc gasket. IIRC a head gasket leak would result in coolant mixed in the oil and even the cheapest shop would charge at least 500 for that job alone. But I think both suggestions above would be a good place to start. Sounds like you're ready for a lot of catch up on maintainence to do, might as well check both.
 
Thanks for the responses, everyone. I really appreciate them.

I ended up taking it to one of the local Mazda dealers, and within 2 hours, they diagnosed exactly what was wrong. 2 coils were bad. I also had engine mount #3 that was cracked, and my belts needed replacing(and yes, I DID ask them to show me the belts and the engine mount before i gave them the OK :D).

It was expensive, but I was treated very well throughout the afternoon that I was there, and I now have a newfound trust in this particular dealer service center.

It runs like a champ(seems to have even a little bit better pickup from a start now), no more engine light. The service manager DID tell me to keep an eye on the check engine light, because the catalytic converter might go out as a result of the coils being bad(something to do with fuel saturation). He told me it's 50/50, but just to be aware of it.
 
(whistle)

Lol - this almost has become my default response for this, because they always seem to go bad. And to the OP, I can almost assure you that your cat has been ruined. I drove half a block with my car and a misfiring coil and it ruined my cat.

Anymore, when people come on here with high mileage cars and ask what they should be doing in terms of maintenance, that's the first thing I say - change your coils!
 
I didn't even know what the hell a coil was until I saw some people mention it here. Thanks!

My ride is still running fine after the dealership fixed it, but now when I accelerate, there's a weird sound coming from up front, or from under the front. Almost like a sort of whine, like a winding up sound. Anyone got any ideas what that might be coming from as a result of the coil maintenance(and belts, and #3 engine mount)?
 
did you ever find anything out?

That weird sound went away after a few days on its own, but now the engine light is on again. The dealership told me when I got the coils replaced that there was a 50/50 shot that the cat. converter might need to replaced down the road, as a result of the coils going bad. The service manager told me that if the engine light came on again, the cat. converter would probably need to be replaced.....$1,200 is what he quoted me! Ouch!! Hopefully it's the 02 sensor. What's the best way to do a diagnostic myself before I bring it in to them and my wallet gets pummeled? I've run the OBII test module on it a couple of times in the past, and it returns general error codes, and doesn't seem to be all that specific.
 

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