i have a 2004 mpv with 116000 miles on it. it was running rough and i was told i needed a tune up. so far i have had a tune up, put new catalytic converters on it, put new manifolds and gaskets and changed all of the vacuum hoses, when we put it on the diagnosis machine at auto zone, all of these codes that say stuff about the exhaust. i have put $2000 in it and it still is not fixed. it runs really rough. when you go to take off, you have to push the gas peddal all the way to the floor and it slowly gets up speed. once it finally reaches the right speed, it runs fine until you have to stop at a light and then you have to start all over again. what could be the problem? i don't know if i want to put any more money in it or not. i love my van, i just wish it would get right. i noticed that alot of people have the same problem. whats up with that?

 

Hi,

My 2004 Mazda MPV is doing the same thing. My engine runs rough, misses, hesitates, stumbles, sputters and stalls during acceleration.

Mine started out during it, especially when my gas tank was near empty. Once I filled up the tank, the car ran fine. Gradually over time the same problem occurred, when my tank was over a quarter tank full. At the same time, I had other problems including: Rich Gas flumes smell and known vacuum leaks (intake manifold gasket and air intake hose needed to be replaced. Plus replace missing EGR gasket).

After I solved my vacuum leak problems, I get the familiar boat foghorn noise at the input of my air filter [my air control valve (ACV) needs to be replaced]. I don’t think replacing the ACV will solve my problem with my problem with engine running rough, missing, hesitating, stumbling, sputtering and stalling during acceleration. With my car in park or neutral it idles fine. The problem only occurs when I am in drive.

The Mazda Trouble Shooting Manual list 44 possible causes. I first suspected a restricted fuel filter or fuel intake sock. Several dealers say the only filter in the MPV is the intake sock but in the Mazda Engine Service Manual says the fuel filter is located forward of the fuel tank below drivers seat under vehicle. Anyway, I checked the fuel intake sock and it’s OK.

Hence, I believe my problem with engine running rough, missing, hesitating, stumbling, sputtering and stalling during acceleration is caused by the throttle position sensor linkage misadjusted (the sensor out of range) or sensor not functioning.

See my thread: https://www.mazdaforum.com/forum/showthread.php?t=23075

 

i think

 

I've no clue about TPS adjustments, but have a few questions and a suggestion.
How were the spark plugs when you pulled them?
After the tune up, in what condition are they?
Reason I ask is I had an odd issue pop up in my old mx3 rs after doing an engine swap. It ran ok at first, but soon it started missing, hesitatiing, stumbling when driving. Plugs were black, from running rich. Replaced them, it'd be ok for a week or so of light driving. Then it'd go back to misbehaving and running like crap, and plugs would be black and smell like gas. On start-up and at idle, it was ok; but driving was very different. Turned out to be a Coolant Thermosensor. The one for the ECU, not the dash gauge. Never threw a code, no CEL. Pulled the sensor, found it was broken. Replaced it, and it ran fine.
It wasn't telling the ECU that the engine had reached running temperature so the ECU didn't lean out the air/fuel. It was running very rich, all the time, fouling plugs.
Maybe this will help, or at least rule out a possibility...

 

You need to take it to a mazda dealer and have a mazda tech that knows the car check it out. They need to check engine compression,coils,relavant pids like fuel trims.ect,mafs etc. You try to save a buck by taking this to autozone for a cheap diagosis. 2000 dollars later it still runs like a POS. Most likley the problem is bad ign coils. The missfires will damage the cats. I wish i had a dollar for each car that has come to me that has been miss diagnosed by the idiot moron [parts changer] down the street. If i sound frustrated i am. It is a crying *** shame that a simple repair can turn into a total expensive nightmare. If some one could post some dtcs. I can tell you the best way to fix this car.sorry about the rant.

 

I have the same exact problem with my 02 Mazda mpv. I can not figure it out