Picked my car up from the Mazda dealer (2005) after paying 800 to have it repaired, and on the way home, it choked down on me three times. Returned and talked to mechanic, and he is baffled. Any ideas?

This happens about once or so every two to three weeks. Will be driving, and sometimes, particularly on a long low grade hill on the interstate like we have here in Ga, car will barely pull the hill, shifting into 3rd or even 2nd to get up the hill. Fortunate to make it at about 45 miles / hour.

Then if I hit the Atlanta traffic on the downside of the hill and come to a stop, car will choke down and very very difficult to start... sometimes doesn't. You can imagine what that does to traffic in Atlanta!

Also at times just driving locally, will do similar things. Example; on way home from dealer, was driving the ten miles to my home on side streets. At first, things were fine. But then when got into traffic, idle started dropping and and entire car shaking/vibrating from low idle... then shuts off in middle of intersection.

When I get it started, I can have pedal to floor and there is no power whatsovere... can get about 10 miles per hour if lucky. Then when stop, again, will shut off. I usually switch to manual and TRY to keep car running long enough to be able to pull off of road. Other day, got it started, and had to creep up the road at about 5 miles / hour until I could pull off... then it choked down.

Usually can't get it started after choking down until it sits for about 30 minutes. And many times after it starts then, it is fine for a couple of weeks.

Have had coils replaced... this last time was told it was a throttle sensor and catalytic converter... replace. Had it "de carbonized"... I do get the "box of rock" noise... and sometimes that seems to be cause... but again, have had it cleaned.

Sometimes when driving it, especially if on interstate, and all of a sudden it downshifts and loses power, the coolant light comes on. Sometimes check engine light on.

This has been going on almost a year. Begining to think no hope of getting it fixed. Any suggestions I can talk over with mechanic? It's in the shop now.

He told me compression was excellent... what do I do? Sell it?

Any help would be GREATLY appreciated!!!!!!

 

A few possibilities remaining:

- Fuel pump is failing and overheating, making it hard to deliver enough fuel, and letting it cool down clears up the problem for now

- Fuel filter is clogged, and relaxing the fuel line pressure lets the clog shift enough to let more fuel through

- O2 sensor failing and giving false readings to the ECU, killing your fuel delivery

- Battery cables/terminals are corroded severely and it shifts around between a solid connection and no connection

- You only mentioned coils, so if the plugs and wires aren't done get those done as well.


I'd also normally point at low compression for many of the low RPM power, idle, and hot start problems, as they are incredibly common for those. However, low compression doesn't just clear up on it's own so I am not inclined to believe that low compression is the root cause here. And if your mechanic doesn't have a rotary specific compression tester, then he can't possibly know what your compression is. It needs to be able to read each of the 3 faces for each rotor and compare the 6 values against a chart depending on starter RPM speed of the test, also comparing values between each other for too great a variance, even if the numbers are sufficiently above the minimum.


A key thing for you and your mechanic to keep in mind is that there are MANY failure points in the RX-8 that should throw a code by conventional knowledge, however may not throw a code when they fail. O2 sensors, cat, and MAF are a few of the big ones that fall into this category.