Jerks/hesitates at 35, 45, and 55 mph
 

Looking for some suggestions. I have a 2003 Mazda Tribute LX, 6 cyl, 4wd, 154,000 miles. No one can seem to diagnose the problem I am having. At initial start/takeoff the car stutters slightly in reverse and slow acceleration. Once I reach city street speeds it shifts/runs fine if there is not too much traffic because I am able to accelerate a little more aggressive. The problem begins when I need to let off the gas and accelerate slowly at speeds starting at 35 mph. The vehicle will stutter/hesitate/jerk if I am accelerate lightly and try to keep a steady speed. If I give it a bit more gas it pulls out stuttering. However, this will happen again when reaching about 45 mph and 55 mph. I have already replaced the TPS sensor, the air idle control valve, and the MAF sensor. I have also brought it to two different mechanics who could not give me a solution? I am at wits end here. I'm trying to be proactive so I don't end up stalled somewhere in need of a tow. Any insight would be great. Thanks.

Did you ever get an answer?
 

We are having the same issue. Do you find out what waswrong?

Thanks,
Joanne

Seek welcome ot the forum

Joanne welcome to the forum

I had similar symptoms. You should get an OBD scanner and check live data to ensure the short term and long term fuel trims are in order. If not, there's a leak somewhere.
Otherwise, you could go ahead and replace the upper and lower intake manifold gaskets, along with the other gaskets provided in the kit. And of course, clean the areas so you get a proper seal.
While you're at it, spark plugs and ignition coils since they'll be easy to access at the same time, assuming it's a V6. Bit of a pain to remove all the stuff just to access the back 3 coils / plugs.

Ok now starting to get what you know and don't know? :cool:

The vehicle in this thread is an OBDII ECU programed system. So, there would be an engine check light and if not there would be DTC in the pending file and the monitors would be in fault or no in state of readiness. There is no reason to check the fuel trims and that would also be on the lower end of a diagnostic list that the problem would be likely solved before you would need to data log them and see what they are doing?

Never, Never Never, change any parts when you have a problem before you first verify the cause of the problem and check that suspected part for failing or failed before you change them. Randomly changing parts unverified failed or causing a problem can and often does cause other problems on top of the original unsolved problem!