My Cougar is bucking on acceleration/gear change!

Discussion in 'Other Auto Tech' started by Grandmaster, Sep 5, 2007.

  1. Hey guys,
    My wife has an 02 cougar with the DOHC 2.5 in it. It's an auto. We just got her a new civic (wanted something four door) and we want to sell the Cougar but just in the last month it started having an issue. The best way for me to describe it is this: If I am going down the road at about 45mph, maybe 1800-2000 rpm and try to slowly accelerate up to 55 (like trying to slowly do it without making the car downshift) it will run like GARBAGE, bucking and missing and stuttering and such. Then if I just hammer the gas to make it shift it will haul right up to the end of the gear with no hesitation. Also if I am sitting still sometimes it just misses here and there, but it is WAY more noticeable when it does like I described above.

    Does anyone have any ideas? I changed the plugs. The old ones looked a little rough, they were bosch platinum +2s, I put in the recommended platinum autolites with the recommended gap and it's still doing it. Maybe I need new wires or a new coil pack?

    Any ideas? Thanks a lot! I need to get this car fixed and sold.
  2. It should be throwing trouble codes. Take it to an Autozone and have 'em hook up an OBD-II code reader to it. That will at least give you an indication whether or not the trouble is ignition-related, as you'll likely come up with something like "Cylinder 1 Misfire" (or whatever cylinder # it would be) or "Multiple cylinder misfire." If you're coming up with a lean code, that could point to a lot of other things. It could be something as minor as a disconnected, broken, or dry-rotted vacuum hose, or even part of the intake tube not being tightened down (the airbox lid might not be snapped shut right, or the clamps to the tube could be loose, messing with the MAF sensor's readings).

    Another possibility is that the EGR valve is getting plugged up with carbon, or is otherwise not functioning correctly - EGR issues usually cause a lot of part-throttle or cruising-speed problems.

    Just a couple of thoughts.
  3. LOVE YOU DAVE. LOL.... Thanks... Master of all small and large technical tid-bits.
  4. Thanks a lot! I actually work at Autozone so I'll roll by there after class today and check the codes. The light's not on but it's worth a shot!

    I actually found a broken vacuum hose yesterday and fixed it but to no avail. I'll check the codes then go from there. Tighten everything up etc. I'm thinking it might be the plug wires. The car has 99000+ miles and I dont think they've EVER been changed.

    Thanks for any more help and for the help already!
  5. Just wanted to post and say that my boss at AutoZone suggested that I take those Autolites out and put in some Motorcraft plugs, because he had a customer who put AL's in his vehicle and it wouldn't run right, but then he replaced them with the MC's and it worked fine. Well, since the car had ran great for a long time on those Bosch Platinum +2's, I decided to trade the Autolites in for a new set of +2s. I did that and the car runs great!

    So I guess that engine just doesn't like the Autolites for some reason. I had the right part number and everything, right gap, etc. Wierd. But I'm glad it's fixed now!
  6. Cool beans. Sometimes, you'll run across that kind of a deal, where different plug brands just won't work on certain applications. The problem isn't so much with the brand or design of the plug, itself, per se ... rather, it's a matter of manufacturers and parts places trying to cross-reference plugs to work on multiple applications. They pretty much only take into account the thread size and overall size of the plug - I guess they must figure, "Well, if it'll screw into the plug hole, it's GOTTA work!" - but the heat ranges can be wayyyyy off from brand to brand. Having a plug that's way too different, such as a way cold heat-ranged spark plug, can result in premature fouling, misfires, and all sorts of wacky drivability issues.

    Autolites are generally good plugs, but mostly just for old-school domestic applications (like 302's, 350's, 305's, etc.). Trying to put domestic-brand plugs into an import motor doesn't always jive because of the differences in plug design between, say, an Autolite and an NGK or Denso plug. Y'know ... metric versus SAE measurements, and so on. They'll list a plug as being a replacement for it, and yeah, it'll physically screw into the head ... but it won't perform the way it's supposed to, because it's sort of a "universal" plug never meant for that specific application. Bosch plugs seem to have better luck running in Asian and Euro imports, from what I've seen, and the newer Cougars are essentially an import of sorts, being that Mazda had a hand in their making. (The newer Cougars were made to be what was to be the third-generation Ford Probe/Mazda MX-6, when some marketing goober thought it'd be cool to slap the Cougar nameplate on it.)

    Anyway, good to hear that you've got 'er running right again. :nice: