hesitates while accelerating

[mitchcurran]

1993 MX3 200xxx kms new distributer, plugs, wires. stutters and hesitates during acceleration. no problems during cruzing speeds oh highway or anything like that, really bad when downshifting. seems to be only when throttle pedal is about halfway or wide open it does it. very slow acceleration doesnt cause it to hesitate. noooooo clue on what to check next... any help would be much appreciated! thanks!

[RS_OBD'oh_2]

tps, vac.. maybe a crappy injector?
Does it happen all the time or just until it warms up?

[mitchcurran]

tps was adjusted at the mazda dealer as well. it happens all the time... im lost.

[mitchcurran]

also the guy that had it before me took the stock air box off of it and put a cone filter on the end of it and than plugged the egr solenoid thing under the box with a screw. i was getting an DTC 16 EGR circuit malfunction code so i just made a hole in the filter and put the vacuum hose in it and used some ultra black silicone to make sure its air tight and havent had a check engine light since. but its still doing it...

[shameem]

Check for cracks in the intake tube or spray some carb cleaner around the intake tube when the engine is idling - if the RPMs go up or down then you got a vacuum leak...

[mitchcurran]

intake tube has a crack in it but its tapped up solid. is air tight. as far as i know, i have electrical tape than duct tape than another layer of electrical tape. i am currently looking for the stock air intake box and tube right now cause the guy who had it before me just put a cone filter on the end of the stock intake tube and im pretty sure that just makes it worse.. im sure that that crack is 100% air tight now though. so dont think its that. but i will find out when i change it back to stock.

[Trivers]

Mine does the same under acceleration it kinda cuts out, then kicks back in. But if you gently roll on it is fine. Let me know if you figure anything out.

Thanks

[Ihatedomestic]

Just had a *similar* problem happen to me yesterday.

The car would bog down, or misfire when under any kind of a load....worse at low RPM, almost fine at high RPM (less load). I could visually see a cloud of black smoke coming out of the back end = unburnt fuel. I had to rev the engine up really high and ride the clutch to get it start moving from a stop.

I was thinking low fuel pressure initially, even though I know I saw lots of black smoke.. I had just changed the fuel filter and used a gauge rigged up from my air pig to test the pressure. It was fine (roughly in the 60 PSI range). Flow seemed to be ok as well.

I had just replaced the distributor with a "new" unit only about 1 month ago and figured that the spark element of the equation was fine, but switched over to my old dist. anyway (which has a bad CPS). Turns out that was the problem. The coil was not producing the energy needed to jump the spark plug gap under load, so therefore no spark and no firing in the cylinders.

So, even though your distributor might be "new", try to swap it with a known good one. Just a thought to help the troubleshooting process

[RX8SE3P]

I'd still personally be checking the TPS. I never trust mazda dealers, they don't know much considering mazda created this car.

Replace that crappy air filter and intake hose with new stuff or a good condition genuine mazda one. Eliminate one problem at a time. Make sure the distributor timing is right also.

[mitchcurran]

one of the oil rings on the valve cover is leaking a very small amount of oil into the spark plug cylinder and covering the plug with oil causing a very very shitty spark if any at all. i jammed almost a half can of intake cleaner down that cylinder used compressed air and blew all that old oil out of there replaced all the plugs and now its working like new. i re checked that same plug about 3 days later and there is no sign of oil so it must be a very very slow leak that the guy that had it before me never noticed until the car started to work like s---. glad i figured it out though. but when buying a used car dont take anyones word for it when they say brand new plugs wires etc etc. cause those plugs were not even close to new i guess i should have checked that out earlier. oh well. workin good now. thanks for everyones help!!!!!