Windstar 3.8 Chugging/Missing

CraigRK · 05-13-2009, 06:01 PM

Here’s the story . . . ANY help appreciated. 1998 Windstar 3.8L ~300,000 km

For quite some time (months) I noticed a slight chugging at low RPM’s. This was slowly getting worse over time, but curiously, would instantly clear up when the engine revs hit 2000. Seemed like a misfire at low revs?

Then, the chugging got much worse, and over the course of a few days spread through the RPM range. The vehicle became virtually undriveable, with the engine chugging and missing. The CEL comes on and flashes.

I tried unplugging the O2 sensors – no difference. At Advance Auto, the guy checked the codes and got O2 sensors codes (they were disconnected at the time) and missing on cyl; 1, 2 and 6. (Duh!) He said those were the only codes.

Although the plugs were fairly new double platinums, I changed all six plugs. Then the coil pack ($85!!!). Then the plug wires. Then the air filter. It seems to have improved slightly, but is still chugging and missing. I have NOT gotten to the root of the problem.

I have a very limited budget, and can’t afford to keep swapping expensive parts. I was wondering about the crankshaft position sensor, the crankshaft angle sensor, I’ve read here about the camshaft sensor(???) and is there a way to test the MAF without replacing it? (I can’t return the new coil pack or sensors once installed.)

Again, any thoughts or insights would be appreciated.

CraigK

mark v · 05-14-2009, 03:58 PM

Double platinums are not required for that engine, may be part of the problem.

What was the exact code numbers?

sunnyford · 05-14-2009, 06:32 PM

The Haynes guide has detailed instructions for voltage testing both the CPS and the MAF.

Think of the Cam Shaft Position Sensor as the computer controlled car's equivalent of the good ol' Distributor. But instead of a bunch of spark plug wires coming out of the top of a big plastic cap with a contact pick-up disk spinning around underneath, today we have a little sensor spinning around at the top of the shaft and it sends a short electrical signal to the PCM (the "computer") every time cylinder #1 passes Top Dead Center (TDC). Then it's up to the computer to make sure the spark plugs each fire at the right time.

In your case, the little sensor on the top could be on its last leg and sending a crappy single to the computer, which then tries its best to do the right thing, but not good enough to go unnoticed by you. Or the sensor could be fine, but the wire from it to the PCM could be shorting out somewhere.

BroncoJoe19 · 05-15-2009, 11:31 AM

Did you give a good look for vacuum leaks?

There are a number of threads here that have a good link for 0174 codes, regarding clogged EGR ports.
I'll bet you end up going in that direction.

If the plugs that you pulled looked good, and you had the problem, and replacing them made no difference as you noted above, I wouldn't go that route, at least not at this time. Those one's in the back are a bit tough to get to.

mark v · 05-15-2009, 12:08 PM

I have a 1998 Windstar 3.8, Double Platinums are not stock or required for this vehicle. Motorcraft #SP-486 is the stock plug and it is Platinum, not double platinum.

I see 22 different types of plugs you can put in this vehicle and only ONE specified stock and it is the Motorcraft #SP-486.

100,000 miles for a plug to last is not long enough for you, double platinums wont last any longer.

Platinum plugs run hot, double platinum runs even hotter.

Quote:

Originally Posted by CraigRK

Thanks for your response.

Several tens of thousands of km's ago, I replaced the original plugs with the specified Autolite APP765's (double platiums). Ran great for many, many miles. The very recent change was to Autolite APP105's which are also specified for this vehicle, and are a replacement for the APP765's (although that replacement by Autolite is somewhat suspect). I went with double platinums purely for longevity reasons, especially given the PITA to change the plugs on the far side. The APP765 plugs that came out looked A-OK, and with just the plug replacement, there was really no detectable difference. I really don't think the issue is plugs, but hell, if throwing in a set of 6 $2 plugs might solve the problem, I'll give it a try this weekend.

BroncoJoe19 · 05-15-2009, 12:47 PM

I'm not disagreeing about which plugs are recommened, and I've seen it posted in other threads the recommendation to NOT use anything but what is recommended.

All I'm saying is that I would put my energies into searching for a different solution (at least for now).

Vacuum leak could be a biggie.

Pulling codes again, and reporting the actual codes would be helpful.

rumbler · 05-15-2009, 01:25 PM

Fuel Injector plugged?

mark v · 05-15-2009, 01:42 PM

Way too many people have used them fancy plugs and developed running issues, dont know one member here who would disagree with me.

BroncoJoe19 · 05-15-2009, 08:15 PM

Mark makes a good point about the plugs, that coupled with the fact that YOU feel the replacement is suspect, then I have to agree that it may be a good idea to swap them out.

Still I would look for a vacuum leak before changing the number 1 plug. The #3, and #6 are easy enough to get to.

Also you might want to start considering a compression test.

12Ounce · 05-20-2009, 06:10 PM

I'm not even sure you can buy the same plugs the manufacturer used on this engine ... it was three with the electrode platinum coated ... and the other three with the plug base coated. It saved a wee bit of cost ... but the plugs had to be located in the correct cylinder. It is much easier to used "double" platinum (base coated and electrode coated) plugs and use them "anywhere" avoiding confusion.

I guess it is true that double platinum plugs are not "required" ... but you will certainly get more life out of them. I think I'm on my third set ... and this set should last until 300 kmiles is reached.