engine sputtering bad need help

A few days ago I noticed a shutter on takeoff. I thought it was the clutch starting to slip. Today on the way home at a light it sputtered an backfired but didn't die, felt like it was running out of gas. The CEL came on for a second but went off. Shut it off thinking the timing belt or plugs. Cranked it up and started fine. Engine pulled strong as ever, but if the RPM dipped lower than 2k it would sputter and run like shit. I was able to limp it home but had to rev it like crazy at stoplights to keep it running. Now its a gamble when I crank it it runs fine or sputters.

I'm thinking a sensor or vaccum hose, but need advice on where to start. The sparkplugs are overdue, would they do this?

Sorry for the jumbled post, I'm posting from my phone...that's why I haven't searched yet.

Thanks in advance.

Oh BTW yesterday I blew a heater hose. After replacing it I hosed a bunch of old old grease angd gunk off the front of the engine trying to see if I had a front main leak. But it was doing that 'shudder' before I did this and I believe that shudder has grown into this.

Again NO CEL at this time...only blinked once.

NGK Blues
http://www.buymazdaparts.com/parts.c...=MIA97&catid=4
NGK Plugs
http://www.buymazdaparts.com/parts.c...=MIA97&catid=4
Do the Fuel filter,
http://www.buymazdaparts.com/parts.c...=MIA97&catid=4
and add a bottle of Techron Concentrate.

Ditto on plug wires.

I think I found my problem. I pulled the plugs to let the plug sockets to dry out if there was water in them. When I put them back in I noticed this...Are these chew marks?? Do I have a squirrel chewing on my engine?

http://img.photobucket.com/albums/v4...i/P1060391.jpg
http://img.photobucket.com/albums/v4...i/P1060392.jpg
http://img.photobucket.com/albums/v4...i/P1060393.jpg
http://img.photobucket.com/albums/v4...i/P1060395.jpg
http://img.photobucket.com/albums/v4...i/P1060396.jpg


Im picking up new plugs/wires tomorrow. That should clear this up. It's surprising they can go this bad so quickly.

Pick up a rat trap or 2 and place 'em under the engine bay on the ground. See if you catch the little bastards that are chewing your wiring.

You may want to check other wires like on the back of the alternator for chewing too.

I have a set of plug wires from my wife's 99 that I'd sell cheap. They're Magnecor wires. I bought another set when I was trying to figure out why her car wouldn't start. So now I have a second set that's perfectly good, so I'd be interested in selling them.

Ok so I changed the plugs and wires...no dice. still sputtering...

Next is the fuel filter, but man I really really don't want to replace the fuel filter. Probably the worst job ive done yet on the car, i'd hate to go thorugh all that and it not be the problem. Is there anything that I coud check first before doing the filter?? I noticed there was a few small chew marks on a hose or two...are there some particular vaccum hoses that could be bad? Im sure they haven't been replaced in the 160,000 miles the car's been on the road.

Im going to pick up one anyway, but i'd love it to be something easy.

What's the life on an O'Reiley's filter? I think I have about 35k on this one, do they go out this quick?

I'd think your filter is fine. Too bad you can't bring the car here. I have a spare cam angle sensor and coil pack that you could try. You think it would make it all the way down to my place?

My guess would be one of those two. They seem to be common failure points for some reason. My wife's started to sputter some when I replaced the coil pack and cam angle sensor last time.

well...now that you mentioned it after I blew the heater hose I cleaned the CAS a little and I just noticed a fretch batch of oil leaking out. I thought the CAS O-ring had sprung a leak, maybe the two are realated??

I did notice that the problem only showed up when it warmed up. it ran perfectly fine for 15 minutes then started clunking.

I could probably make it back down there...but it would be tough. It only seems to die at stoplights...I think I could keep it runing, but i'd risk breaking down on 360. Do you have the time today?

http://forum.miata.net/vb/showthread...+sensor&page=2

Reading this thread, sounds like it could be the coil packs or the fuel pump. Also rules out the fuel filter since the problem goes away at higher RPMs. Since my car was/is low on gas im going to limp it to the station and fill it up see if the problem changes..this guy says his problem got better the more gas was in the tank,and his fuel pump was going out as well. That might help narrow it down.

Filled the tank...exactly the same. The problem seems to be slowly getting worse. Before I turned it off is sounded like it was running on two cylinders, untill I could get the revs up, then it would pull nice and strong. Now it's throwing a CEL when it dies...but gows away when I crank it.

A few quotes from that thread...

Quote:

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A coil-misfire will throw a CEL pretty quickly, are you getting one? Most times it will be flashing when it starts missing.

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Quote:

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The coilpack swap fixed the major "hiccup" while driving.

The new fuel pump fixed the power loss on cornering.

---

Not today, but I should have some time tomorrow afternoon. The cam angle sensor on the 94 is on the front of the valve cover right? That's where it is on the 99. I know some year models (1.6L?) had the cam angle sensor in a different location.

IIRC, the coil packs are the same for 94-99.

http://www.flickr.com/photos/pethier...7594256422537/

The CAS is on the driver side of the back of the valve cover. Are the same for the 99 cars?

No, 99 is front right side of the valve cover. Coils are the same, IIRC, though.

Did your Rats eat a vacuum hose also? I'd look for more stuff they ate I'm sure they didn't just eat the plug wires.....

Yea ive been looking around, but honestly I don't know what im looking at. Im a novice at car stuff, I can do basic work but the vaccum system is beyond me. Any particular hoses to look for? I checked the ground wire on the front of the engine, it felt tight.

I noticed this on one of the plug sockets that came off the car. Does it look like a condensation buildup? Looks kinda like what I found on the magnacore website. http://www.magnecor.com/magnecor1/main.htm

I pulled them yesterday to let any water dry up, but it started raining while I was at the library (hood was closed though) so if there was condensation it might not have dried out. Would the new plugs / wires have solved this though??

Here's the pic...
http://img.photobucket.com/albums/v4...i/P1060402.jpg

So last night at the advice of William and Gary I checked for engine codes: none, jacked up the car and banged on the cat with a rubber mallet: no marbles, very solid sounding. Then I cranked it and bumped up the idle. Funny thing, the car ran solid no spuddering for about 30 minutes. I decided to take it out on the road. Felt good so I drove it a good 40 miles up to Stevans place at Propwash. He checked all the vaccum hoses and everything else, we hung out for a bit, then drove back home in the rain. No sputtering at all. Drove fine to work this morning, pulls as strong as she ever did.

3 things I noticed. First, it might be the advanced idle, but the car feels like something's not right, the idle is funny. When you let off the gas it idles at 1.5k for about 5 seconds, then drops back to ~800. Also seems to be up and down like this by itself periodically.

Second, the lifters were clattering something awefull. Ive never heard them clatter that bad. It is time for an oil change, that must be it. That was going to be last week before all this crap happened. I'm not saying it's related at all related at all, just very strange.

Third, there is a noise we noticed under the hood while running, an intermittant, holow plasticy bump noise. Sounds like gurgling coffee pot, or something bumping the hollow intake. Steven listened to the engine and concluded it was not in the engine, but in the intake or something like that. Again, maybe not related, but just very strange.

This weekend im going to attempt to change the oil, air filter, gas filter, run a bottle of Techron, and do a seafoam job. We'll see if it comes back when the gas tank get's low. For now im still...:confused::confused::confused:

I really appreciate this forum and everyone's help. Yall are a real lifesaver. I'd be in bad shape if I wasn't on here. Thank you everyone (71DSP, Black Roadster, Gary @ TDR, and Rogue in particular).

What is the timing set at? When's the last time it was checked?

Umm...Titus set it for me a couple years ago. IIRC we set it to 12. Is there a possibility of it slipping out of time...over time by itself?