Hello,

99 Mazda Protege, 1.8

I was getting OBD code p1170 and p0710 on my 99 Protege (1.8 engine) and replaced the top o2 sensor. The problems seemed to subside for a day or so, then the check engine light came on again a few days later. Now I'm getting the original two codes plus an p1141, so I just went ahead and changed the other o2 sensor (the one on the bottom of the car). I'm still getting the same symptoms. The car idle's low when at a light and seems like it wants to turn off at times. There's also a major loss in power. I cleared the check engine light with the OBD tool I have, so I'm just waiting for the light to come back on. I read somewhere on the net that it might have something to do with the mass airflow sensor. Should I change it? I'm getting tired of this! My dad sells me the car and now all the problems come out! I have about 140K on it. Help!!!

 

As I was trying to locate the mass airflow sensor, I saw that the hose extending from the air filter was cracked almost all the way around. Since no autoparts stores carried that and the dealer wasnt open, I gave it a few rounds of black tape, followed by duct tape, followed by some more black tape. Viola! So far so good. We'll see if the CEL comes on. I doubt it. The drop in air pressure was probably enough to make the car idle low and stall.

Hopefully this will help someone else with these symptoms!

 

I just changed that hose on mine, since I had the same error codes.

It is about $45.99 to get a brand new one from Mazda

 

I've noticed a lot of references to that cracked tube being a hard to diagnose problem. I can understand why. If the MAF sensor is working properly, but air is entering the intake manifold downstream of the MAF, then that's got to play hell with the fuel:air ratio. The injectors don't spray enough fuel and then the Oxygen sensors don't see what they expect in the exhaust stream based on what the MAF says is coming in. Then the pre-cat OX sensor remains inactive due to a lean mix, and that screws up it's relation to the post cat sensor. It is the pre-cat to post-cat sensor activity ratio that trips the cat efficiency code.

A little crack in a piece of plastic tubing turns the whole high-tech electronic engine control system into mush!

Man! Ya gotta love the miracles of modern technology -- huh?

 

had the same problems you descibed , but different code on 2001 protege w/ 2.0L, didn't see the crack until I moved the intake hose and the idle dropped. replaced with new (didn't want to rebuild old hose w/ tape) hose . CEL hasn't come back .

 

I've got a '99 1.8L SE, 92,000 Km. I had exactly the same problem. The duct material and layout practically guarantees this problem. I didn't waste any money on anything else though. I was going to squirt some cleaner onto the MAF, and saw the split when I disturbed the ducting. I did a tape job pending arrival of a new duct. When I replace the duct I'm going to cut a section out the old one, insert a true flex section, and keep it as a spare.
In the coldest part of the winter, that duct material is like glass. The other solution would be to take off the filter box and modify its mountings so they're more compliant, then the whole box/duct assembly would move as one unit, taking the stress out of the duct.