Running rough and missing

[Super-Merc]

Good day all, wish I could say the same here. My 2003 started missing every now under low RPM conditions gradually getting worse. I thought coil packs. I took off the covers and all looked good on the driver's side but the passenger side had coolant under the cover and the last sparkplug hole (number 8?) last one in the back was full of old coolant. I replaced the coilpack, dried out the hole and checked the plug. Started running better but in one day started missing again and catching every now and then during mid-range. I have not checked for coolant in the hole again today. Before I changed the cp I noticed it was more difficult to turn the steering wheel but that only lasted one day. I just turned 150,000. I don't have the cooling mod and have never had a problem other than the thermostat sticks every once in a while but the gauge never pegged out and it was only for a few seconds only on initial start of the day.

[STEPS]

are you running a tune ???
are there any check engine lights on ?
have run any injector cleaner thru th fuel system?

[MyO4Rawdur]

Only thing I can think of is a head gasket but that would be like a really bad situation where it goes in the plug tube.

[Super-Merc]

I am running a tune for my 4.10's, no check engine lights and I havent run any injector cleaner fluid through it. I ran some non premium gas for a couple times, just didn't have the money. I also have to add that was was military base gas and sometimes it can be less that desireable at times.

Thanks for reading this and posting,

Rob

[Super-Merc]

I forgot to add that I checked the oil and there appears to be no evidence of water in the oil. I had it changed about 3 weeks ago and it still looks great even at 150k. I don't see any leaks in the engine compartment either.

[MyO4Rawdur]

Did you replace the number 8 plug ? What color was the old one and can you pull the new plug or current plug and check the color

[Super-Merc]

I pulled the plug out of #8 and the one next to it, they both looked great nice light chocolate color. I did not see any signs of misfire or water. Thanks again guys and gals for looking and trying to help.

[a_d_a_m]

Hate to sound like a broken record (as I've said it several times in other threads for other people) but this problem seems to be popping up a lot lately as these cars age. In my opinion, the coolant in the #8 spark plug tube is probably directly related your issue.

Wouldn't be the least bit surprised if your head gasket is F'd and one or more of the valve seats on cylinder #8 are going sour. Especially if your car hasn't yet triggered a check-engine light. Sounds like an early manifestation of the problem I had. Without seeing the car, all I could suggest is start with a compression/leakdown test. If you have zero compression on 8, and air passing through the left exhaust pipe on the leakdown test.....you need to read this thread:
http://www.mercurymarauder.net/forums/showthread.php?t=82117

[a_d_a_m]

To the O/P - any chance you can get some video of it running, both under the hood and at the tailpipe? With a few revs, preferably, so we can really hear it.

If it ends up being a zero compression issue on #8, you'll want to unplug your fuel injector for that cylinder so it isn't dumping gas into the cylinder and washing out the ring.

[Super-Merc]

Hey thanks for the link to the previous post. I was really hoping it wasn't going to be the extreme but that is where I was heading as well. I think I can see from the pictures the drivers side came off on your car? My angryness is on the passenger side rear. Is that #8? Sorry, I should probably know this. I will attempt to get some video and sound but will attempt a compression check first.

[a_d_a_m]

Ohhhhhhhhhhhhhh I failed at reading apparently! I didn't see that your issue was on the passenger side.

Traditionally, the driver's side (5-6-7-8 front to back) is the issue, not the passenger side (1-2-3-4 front to back). Though I suppose anything is possible.

No check engine lights though?

[Vortech347]

Run a compression check and a leak down test.

For coolant to get in there would require quite a bit of it in the oil then it would need to push its way in through the valve/cam cover O-ring. After the engine is running do you have milkshake oil at all? Are you sure it was coolant and not water from a car wash or something?

Is the car smoking?

[Super-Merc]

Hello again, update, the car ran slightly rough this morning on my 7 mile trip to work. It idled rough but seemed to even out at highway speed. But as I drove it home tonight it ran very well, no miss at idle or highway speed. Maybe this is good as I would think a dropped seat would be a constant miss at any engine speed. I don't know what is going on at all. I am hoping the bad gas I may have run through it may be the culprit. The water around the coilpack may have been from a carwash but it looked my coolant all nasty brown. I have no coolant in the oil at all.
On a different note, my oil pressure (autometer pro comp actual gauge) has been sticking at zero when the weather is cold outside then popping up when the engine is warm. Has anyone had a problem with the sending unit or gauge? I am sure I have oil pressure or the motor would have exploded along time ago.
Again, thanks for your time.

[JBFTech]

Water in the plug well is most likely from a car wash or big rain etc, replace the coil cover gasket next time you have it off, and make sure you silicone around the harness in the back, top AND bottom. The coil may be alright, however, the longer they short out in water, will cause damage.


Sent from my SR-71 using Tapatalk

[RacerX]

You cannot get JUST coolant in the spark plug hole unless it is coming from up top. The plug hole goes from the bottom of the cylinder head up to almost the top of the cam cover. There is a metal/rubber coated gasket that seals in between the cam cover and spark plug hole. You can get oil in there with a bad gasket, not coolant. If you have a mix of coolant and oil getting that high up. You're already in deep doo-doo. I think it may be a leak in one of the heater core hoses getting right in where the cabling goes under the COP cover in back. You could use some rtv (I like "The Right Stuff") to seal the cable in better once you clean the hole out real good.

[a_d_a_m]

I would think a dropped seat would be a constant miss at any engine speed. My car started ticking a day before the seat finally dropped enough, which at that point pops the lifter/rocker out of place. That's what causes the rough idle/running. If your car is running okay sometimes, then we can rule this out probably.

The water around the coilpack may have been from a carwash but it looked my coolant all nasty brown. If your coolant is 'nasty brown' it needs to be changed...yesterday.

On a different note, my oil pressure (autometer pro comp actual gauge) has been sticking at zero when the weather is cold outside then popping up when the engine is warm. Has anyone had a problem with the sending unit or gauge? I am sure I have oil pressure or the motor would have exploded along time ago. The oil pressure gauge in these cars is basically a dummy gauge - the numbers on the gauge are BS unless you swap in a real one. Billy Bishop here said it best - it's basically a switch that reads whether or not you have oil pressure. If it is reading zero...I would be very, very concerned.

Sounds like this car has a few troubling issues that all ought to be tackled at once.

[a_d_a_m]

Super-Merc, where are you located? If you're nearby, I will come look at the car. Maybe someone else would be willing if you're somewhere else...

[Super-Merc]

Again, I have to say thanks for posts. I couldn't see how coolant could get in there either, just didn't make sense at all. With no coolant in the oil, no white smoke, and no coolant loss, I kinda ruled out a head gasket. I am trying to fix the oil pressure gauge now and hope my miss gremlin stays away now. And of course, my blend door actuator just failed. Still love the car though.

[Super-Merc]

I am located in Crestview, Fl just east of Pensacola. My oil pressure gauge had been replaced before I bought it with the one that actually reads the pressure by Autometer. It goes right up to about 60psi when the outside temp is warm and the engine is cold but fluxes around alot then hovers just off of zero when the engine is warm but can be very inconsistent. I thought the aftermarket sensor may be failing. (hope)

[RacerX]

I'd get a new sender unit for that asap. If it tuly hovers just off zero @ hot idle, you have a ticking time bomb. Piece of mind for $30.

[03mmmonroe]

I am located in Crestview, Fl just east of Pensacola. My oil pressure gauge had been replaced before I bought it with the one that actually reads the pressure by Autometer. It goes right up to about 60psi when the outside temp is warm and the engine is cold but fluxes around alot then hovers just off of zero when the engine is warm but can be very inconsistent. I thought the aftermarket sensor may be failing. (hope)

i have replaced my Auto meter sender for the same concern.

[Super-Merc]

Anybody know what the p/n might be for that sender and where to get it? Summit?

Thanks again

[RacerX]

Autometer sender part #2242 You can get this even at some auto stores like Autozone.

[Super-Merc]

Hey guys, the car seems to run better, still skips sometimes when I lug it. Thanks for the P/N for the sender, got one on order today from Advance. You guys are great!:)

Rob

[Super-Merc]

Hey guys, changed the oil pressure sender and have oil pressure again. Thank you for the part number. The car seems to be running better and better every day. Now if I can get the blend door actuator fixed all will be back to normal again.

Thanks again,

Rob