Idling horrible when stopping
 

This just happened last night. On the way to my in-laws for dinner and the check engine light came one (Again, had it checked about 4 months ago and found out my manifold is cracked, lovely) They said I can drive it and the light may come back on, but it wouldnt cause any harm.

So it was VERY cold last night, and on the way to taxi one of the grandmas, I stopped at a red light and thought i was going to stall! Every time I reached about 5 MPH ready to stop that car would start "jumping" Once stopped it idled kind of rough.

I will add that I drove it 750 miles to Maine and around up there for about 7 weeks, then 750 back to PA, and thats when it started running like crap.

We bought our 2001 MPV in April, so this is the first winter of owning it. Any ideas what may be causing the "jumping" problem? I am taking it in to have the oil changed and all the fluids topped and the tires rotated, and going to have them look at the brakes too. Thinking I am out of line as there is a big pull to the right while driving (Again, just happened since we drove it back from Maine) Had brand new tires put on about 2 months ago too.

Beyond irratated as it seems every used car we buy there is something wrong. Just put new wheel bearing on our Grand AM (Not once but TWICE) and it doesnt even have 60k yet, grrrr.

Thanks!

RE: Idling horrible when stopping
 

CEL on again means a fault was detected and engine computer is letting you know. What manifold is cracked? Have run across a number of 2000-01 MPV with exhaust manifold cracked or warped but they only set a CAT efficiency code due to the air intrusion from the crack/warpage. That should not cause any kind of idle issue. If you get a chance, check out some of your local parts stores to see if they give a free check of why the CEL is on. Many do now as they can give a quick scan for codes and then try to sell you a part to fix what they think is wrong. Ignore the diagnosis but remember the code # they provide. Should start with a P and have four number digits after such as a P0400 or P0306. Post back with what you find out from this with code #.

RE: Idling horrible when stopping
 

Our 2000 MPV just started doing the same thing. Happened during the onset of cold weather. I took it to Autozone and they diagnosed with two codes (unfortunately I didn't record code numbers) "left bank lean" and "right bank lean". Based on this they reset the CEL and I put a can of drygas in the tank assuming that we had water in the fuel. Now 2 wks later during another cold spell, the van started to idle rough again and shortly thereafter the CEL light came on. I would appreciate any suggestions on this.

Could a situation discussed in an earlier post of a cracked manifold lean out a fuel mixture and cause above issue?

Thanks for all of your help!

RE: Idling horrible when stopping
 

The system lean bank 1 and 2 should have been a P0171 and P0174. A crack in the exhaust manifold could dilute the exhaust with oxygen and fool the oxygen sensor into thinking engine was lean as long as the crack was either upstream or very near downstream of the front O2 sensor. Have not seen any cracked exhaust manifolds on that engine but have replaced a number of them due to manifold to head surface warping and causing exhaust leak. Something else that have run accross in the past is a vacuum leak from the intake gaskets between the upper intake plenum and manifold runner control housing. Mazda has even come up with an updated set of gaskets to solve this very problem.

RE: Idling horrible when stopping
 

Many thanks for the help. The local Mazda dealer is partway through the repair. They found the front exhaust manifold to have 1 broken bolt and a large warpage issue. Resurfacing the manifold and they believe that they should look at the rear bank based on their findings with front bank. They have not eliminated the intake gaskets but started w/ the exhaust. I should also note that we have had a continual burnt oil smell after highway use when pulling into a rest area for example.

Thanks again for your help. I believe that it's pointing the techs in the right direction.

RE: Idling horrible when stopping
 

If they do get onto that rear manifold make sure they give a good look to the timing chain gasket up towards the valve cover area. Has been know to leak some oil that then runs down onto the exhuast pipe near your front crankshaft pulley and makes a considerable burning odor. They will be right there with the alternator and bracket off anyway to access the right bank manifold and will be easy to inspect.

RE: Idling horrible when stopping
 

Thank you. We had the codes read and there were 3 and two pointed to the catalytic convertor. So we are having that replaced. As weird as it sounds, I think the jumping that was going on was slush frozen up under the wheel wells, and when we slowed down to stop, it was catching and jerking the tires. I removed all the build up and it didnt do it anymore.

Apparently the MPV has 2 covertors??? and we dont know which one is having problems yet, the mechanic will let us know. I thought the convertor was covered under the emissions warranty??? (Thought I read that in the manual, but its prob not true)

Not sure which manifold is cracked, it was found because the CEL came on right after we bought it and they found someone had attached a part with aftermarket screws and not Mazdas.

RE: Idling horrible when stopping
 

The california emissions MPV actually has 3 converters. Federal emissions only has one. You are very right. The catalytic converters are covered for 8 years or 80,000 miles for Federal vehicles and 7 years or 70,000 miles for California vehicles. Do you happen to remember the 3 code #'s that were stored. Should start with a P and then four numerical digits such as P0421?

RE: Idling horrible when stopping
 

Okay, a dumb question. What is a Federal vehicle? We live in PA, so the CA wont cover it.

I am looking for the print out of the codes we got, i'll post them when I find them!

Thanks!

So if it is covered, do I just make an appointment with the local Mazda dealer then?

RE: Idling horrible when stopping
 

Oh, and I checked and the problem with the manifold is this: (From the service form) "Slight crack at manifold pipe convertor assembly." They quoted me $781.00 to have a new convertor assembly installed.