Contour Enthusiasts Group Archives Forums General Troubleshooting car stumbling between 45-50, p0420, others

96 contour 4 cyl duratech vin3, 108k miles

Acceleration feels extremely sluggish between 35-50. Also, between 45-50 the engine seems to.. stumble real bad. I can feel it skipping. The problem seems to be avoided if I floor the gas and accelerate up from 20 or so rather quickly.

Also, on occasion the car will idle roughly after it's warmed up sitting at a traffic light. It isn't completely uncommon for it to stall at this point. I've also had problems stalling while swtiching between drive and reverse.

Lastely, the temperature gauge isn't working [it never rises from the lowest point], but the heat works fine. I'm fairly certain it's just the temp sender, but I figured it's worth including.

The oddest part about the car is that these problems seem to come and go. I can't really explain it, but it seems like it has some bad nites and good nites.

Recent work:
-replaced IAC valve [past week - seemed to solve most idling problems, but not all]
-changed oil [past week]
-replaced battery [past month]
-fixed head gasket leak [month or so ago]
-changed spark plugs, filters, trans fluid [@100k miles]

CEL CODES:
-P0420 [bad cat, the light comes and goes]
-I'm pretty sure I had a light coming and going reporting that there was a misfire in cyl4 a while back. I think it got cleared when the plugs got replaced at 100k, but I'm not certain.

I think that's everything. I'm gonna try to clean the maf sensor in the next couple of days. Could it be the bad cat causing all the problems? If so, how complicated of a task is it to gut/cut it out? It really isn't too big of an issue legally here in Michigan to ride without it.

Any help would be greatly appreciated. Thanks!

First thing first: It's calling a duratech was a typo. It's a zetec.

I've now also cleaned out the maf sensor and replaced the fuel filter. The idling problems appear to be gone and the p0420 code has yet to come back on [it's been about 2 days].

However, the stumbling problem still won't seem to go away. It seems to happen right around 3500 rpm and will stop shortly after 4000. It's most noticable while accelerating up hills. The engine will bog down and start to skip/stumble/misfire/I'm not sure. After a while driving around I've also noticed that if I hit the o/d off button right as I feel it starting to happen, the problem is averted.

Any help/suggestions would be appreciated.

The stumbling is a misfire. Pretty clear from your description.

Revisit your last plug change. What plugs were installed?

If it's not the plugs, it'll be the wires, possibly the coil.

Steve

420 code is popping up again. I'm pretty sure it's a plugged cat at this point. It feels like it can't get enough power to get the rpms up high enough to switch into higher gears when it needs to. Is that a possibility? And would it explain the stumbling?

I don't have the cash for a new one and I'm past the warranty coverage. Emissions testing is non-existant in MI as far as I know, so I'm left with two options. Cut it out and replace it with a test pipe or straight out gut it. Any information on the correct way to go would be of great help. Thanks!