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This week's riddle is a 1992 Dodge Stealth DOHC V-6 running on four cylinders

I bought this Dodge Stealth in DEAD condition very cheap on Tuesday. The owner said it had a bad engine. I think it’s just a little naughty. It had nearly new tires and a nice stereo, so I figured I’d get my money back even if I had to sell it for salvage. First off I put a good battery in it. The old one wouldn’t even allow a jump. It fired right up, but ran poorly. It is full of coolant. There is no steam coming out the exhaust, no bubbles at the filler, and it doesn’t run hot. There is a coil pack on the left (as you stand facing it under the hood) end of the engine. (Actually the right side.) I can pull the individual wires off as it runs, and two of them make little, if any, difference. The coils for those cylinders continue to throw sparks to ground, as do the “good” ones when the plug wires are removed. One of those bad cylinders is on the front. I pulled the front plugs and found the bad one to look wet, probably with gas, although I couldn’t smell it. Cleaning the plug made no difference. The compression on the front three cylinders is even at about 140 PSIg. Cranking with all six plugs in place and the ignition disabled is even. It seems the compression is probably good. Pulling the rear plugs to check compression involves having to pull the intake manifold. I’d rather not have to, but will if I have to change injectors. I THINK that’s probably where we’re going.

The MIL was on, so I tried to read the flashes. I did the ON-OFF-ON-OFF-ON with the switch. The MIL went off, and did not flash for over a minute. Should It take that long? I’ve been spoiled by OBD2 for so long that I forget. When I restarted the engine, the light stayed off for a bit, then came back on again. It did that three times. so I guess that’s not going to tell us anything.

I am suspecting bad injectors, but since it is not a fun job to get at them, is there another way to clean them adequately? Miracle in a can? I don’t have any fancy equipment like a motorvac. It would be nice to hear that there is a simple (read cheap) fix, but as little as I have in this thing I’m willing to spend some money or do some labor if necessary.

The on-off-on-off-on trick works with Chrysler vehicles, but may not work with your Stealth, as it is actually a rebadged Mitsubishi vehicle I believe, so it has a Mitsu ECU and you’ll probably have to use a scan tool.

Bad or clogged injectors could easily be the cause. Anything that fouls up the fuel/air ratio can cause a misfire. If the misfires were occuring on all 6 cylinders, sort of randomly here, randomly there, you’d expect the MAF or some kind of air leak. Maybe a coolant or air temp sensor. Or a fuel pressure regulator.

But since the misfires are always on the same 3 cylinders, unless there is something linking those three (like they are all adjacent to each other, or all at the end of the fuel rail, etc … I agree w/you, injectors seem to me to be the prime suspect. You might try replacing just one of them and seeing if that fixes the problem for that cylinder.

If this were my car, the first thing I’d do probably is figure out how to read the MIL code properly. You’ll need the manufacturer’s service manual or a Mitchells or the AllData car repair database service probably has it. Your local public library probably has one of these sources at least.

I’ve never heard of anyone successfully cleaning faulty fuel injectors. But it might be possible. Maybe Google “how to clean clogged fuel injectors”.

As you say, there’s always the possiblity of an electrical problem too, but it looks like you’ve already come close to ruling that out. I like to see these cars fixed up and put back to work. Better than in the crusher. Best of luck.

@oblivion Good point. I had not thought of that. It’s really a Mitsu 3000 with a Dodge skin. I don’t have a scan tool, and of course the guys at Autozone are only equipped for OBD2.

I forgot to mention that I can feel all three of the front injectors clicking as they should. I’m sure that the one in question could still be completely plugged and click like a new one.

Best of luck with your Stealth. I have put 90,000 miles on my 1992 model since I bought it in 2000 (currently approaching 150,000 miles total).

A good source for 3000 GT/Stealth parts is www.3sx.com.

I suppose you could try moving the fuel injectors you suspect are bad to other cylinders and see if the problem follows, if it’s not a total pain to get to them. A guy I used to work with had the turbo AWD version of your car. It was very quick and handled great. He had a lot of trouble with the AWD system though. It didn’t help that he beat on it all the time.

@MadMichael Thanks for the link.

I took a look at the link from MadMichael. Their prices are about half of Autozone’s but still over $50 each. I took a bet and ordered a complete set, still connected to the fuel rail, from a salvage yard in western Nebraska that I found on www.car-part.com for $55 delivered. Surely three out of the six will still be good.

Should I try cleaning the “new” ones with lacquer thinner (AKA carb cleaner) before installing them on the car?

I hope that works…I would leave the injectors alone, just install them and see what happens…Maybe you will luck out…