Questions and Answers
Mazda 626 Stutters And Stumbles
Q. I last wrote to you regarding a stuttering problem and have not heard from you. I guess your busy. I recently brought my car to a dealer to fix a missing or stuttering problem. At first it was diagnosed with a spark plug problem. So we changed those. This did fix the engine light coming on, but it still missed or stuttered when accelerating.
Next they checked it again and they felt it was a coil pack. So we changed that. It still did it, and then we changed the fuel filter, and did the 96,000 maintenance package, which included the timing belt, brake fluid, & transmission fluid. This seemed to clear it up for a while but it is back again. Each time we did something it seemed to improve the problem, but it always came back. This work was all done in the last month and a half and cost me $1,000.00 CDN.
Just before we changed the timing belt the problem disappeared. But now after 2 weeks of working well it is back again. The problem is worst at low speeds in the lower part of the gear. For example when I go 60K/hr in 4th, it just gives a little stutter or jerk like it is missing. When this happens it seems to lose power and then it regains it and works again.
Do you have any ideas on what to check next? Call me perplexed.
One thing I did notice was when I brought the car home after changing spark plugs was that the mechanic did not tighten any of the spark plugs. I noticed this as it was still missing so I opened the hood and checked to see if the wires were connected properly. While I had the wires off I checked the plugs to see if they were tight or not and all 4 plugs were loose, and I tightened them. Could this have caused the coil pack to malfunction or burn out. The dealer said this would not be the case.
1998 Mazda 626
2.0 liter engine
Manual transmission
97,000 miles
Fuel Injection
P/S - A/C - Cruise controlPlease write back and help me out.
Thanks...A. First off let me say that if I got your first letter, I would have answered it. I don't pick and chose and I answer them in the order they come in. It might take me three or four days to get to them, but I do eventually.
I would look at the Throttle Position Sensor (TPS) as the probable culprit. I have seen many Japanese cars exhibit this symptom and it is usually due to a bad TPS. For some reason they develop a bad spot and every time it hits there, the symptoms appear.
The loose spark plugs might cause problems for the coil pack. The loose spark plugs would make a high resistance connection and cause the coil to have to fire at a higher voltage.
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