Hey everybody... My mother'* Intrigue is acting up, and I've exhausted all ideas on my end to solve the problem, and no dice.

OK, first the background. 204,000 miles, Series II 3800, original motor/tranny, and for its age and mileage, the ol' girl has been VERY good to us.

Recently, sometimes the car would fail to start when cold. When it would start, it would either run perfectly fine, or it would run really rough and the SES lamp would constantly flash.

I disconnected the battery, replaced plugs (one was original - long story), wires, all three coil packs, reconnected the battery, re-calibrated the VATS BS, and the car ran perfectly after that. A few days later, back to the same behavior.

I invested in an OBD-II to USB cord, and with it, got OBDWiz. Pulled the codes, and this is what I got:

5/6/2014:

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I reset all codes, car ran excellently, it did its full relearn and all emissions systems passed. I was thrilled, but that was short-lived. The next day, back to the same old crappy running, SES flashing.

5/7/2014:

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Checked plug, wire, and everything for cylinder #4 looked fine to me. Reset the codes again, performed idle relearn, and we were "right as rain" for a few days.

Now, occasionally, it has the same symptoms of randomly running like... Well, how many different ways can I say CRAP? But now, no codes stored, and SES doesn't flash anymore.

I hate to say it, but I'm leaning towards a flaky ICM or ECM, but since those are costly parts to just swap out for ***** and giggles, I'm not quite ready to throw money at random parts hoping for a solution. Any ideas?

Also, for many years now, the traction control/ABS module has been bad. We have been driving this car for ten years or more without the ABS and Traction Control functioning. Frankly, I don't care for the oversensitivity of the ABS system (under "little old lady" braking, a manhole cover will trigger the ABS and next thing you know, you're coasting through a red light while the brake pedal fights you), and the traction control system is the worst thing to put in a car since I can't tell you how many times I had to disable TC just to get through the snow. I HIGHLY doubt this is related, since we've never had any issue once the TC module went kaput. Not sure if it was even worth mentioning, but why not? LOL

Due to financial constraints, a new car is not in the cards for us. We're also of the mentality that, if it can be fixed, it'* not worth hauling to the scrapyard. This is the 7th GM in the family that we've put over 200K on the clock, and this is the "newest" car we have (I got it off-lease with 27,700 miles in '03). And I have to admit, when she'* running well, she'll STILL blow the doors off of a lot of cars out there. In '04, going through the Catskill mountains with AC on, doing 75-80 on the highway, I got 36 MPG. Not too shabby, eh?

This car still has original head gaskets and intake gaskets. Yes, I know I'm tempting fate - but as far as I can tell, there'* no leakage, so I'm hesitant to rip things apart that don't need it yet. My mother may be very poor at upkeep, but she does check fluids frequently and has never ever beat on a car. We need to get to the bottom of this because we need to get through emissions and renew registration.

Is this the point where I can cuss out the State of CT'* Emissions program? LOL... If you have the MIL on, you automatically fail, regardless of actual tailpipe emissions. And in order to automatically fail for the SES light, you have to pay $20 first. Talk about a racket...

i would feel lucky you made it as far as you did before having to replace the upper manifold and lower. i have 200 on my 98 and did it again last year, now they have the dorman upper that has all the fixes and felpro aluminum lower gaskets, if they had those when i did it the first time wouldnt have had the second. its exactly what mine was doing misfire codes and slight loss of coolant, maybe an inch in the bottle every two weeks

Oh, I've known for a few years now that I was running on borrowed time with the UIM/LIM. I guess the good thing is that, after my mother got laid off (round trip 70-80 miles a day, 6 AM-7PM), her new job she drives 3.2 miles a day, 6 times a week. Not a lot of mileage going on the car right now, so it'* "safer." Sadly, the vastly decreased mileage makes it harder to track any significant coolant loss. I'll keep an eye on that, though.

She *was* leaking coolant for quite a long time, but it was first the radiator, and then those stupid plastic coolant elbows (Dorman #47065, or if I tear it apart again I'm putting on the Dorman #47065HP metal ones, now that I know they make them - Thanks GMForum!), and then the lower hose clamp.

I did check the 5 Iridium plugs that I installed 110K ago, and the one OEM AC Delco plug from the assembly line, when I did the tuneup. I didn't see any evidence of coolant burn and no oil burn on the plugs - I was shocked, I tell you - although there was a slight bit of carbon on #2.

I've always had her drive the car on local secondary roads shifted into "3" because in "D" the engine will literally turn 700-750 RPM at 50 MPH, (locked in 3rd, 850-900 RPM) and her route has several small hills where the car would go in and out of OD constantly (or lug along in OD because she didn't need to hit the gas hard enough to force a downshift). At 45 MPH in D, the AC won't even keep the car cool because the engine is turning so slow. She drives very conservatively when it comes to acceleration. She'* actually pretty darn good with brakes, too... So finding a slight bit of carbon on a plug after 110K without the benefit of a monthly rip down the highway to clear it all out I thought was acceptable. Maybe there'* just a butt-load of carbon on the valves?

I have a sneaking suspicion, and the "oh-****, look-at-all-I-gotta-tear-apart" feeling in the pit of my stomach, that you might be right on with the UIM/LIM gaskets. Expired registration, due to emissions testing and stupid OBD-II crap, so we really don't take it anywhere other than my mother'* quick jaunt to and from work. Hard to keep an eye on the coolant, but like I said, it'* a good idea and I'll make sure she tells me if she adds any. I gotta get my LeSabre running so she has something to drive while I tear her car apart.

I don't get under the hood of that car very often, but when I do, the fluid levels are good - but she'* savvy enough to take care of that. Even to the point of having pictures in her cell phone of the type of coolant and brand/type of oil I want her using, so she puts the right stuff in. I trained her well. Each fluid has its own funnel in a Ziploc bag in the trunk, and that was her idea. She doesn't know a thing about cars, but at least she can check fluids! (Everything else can go to hell, but the fluid levels are good! LOL)

the thing that bothers me a bit is the poor running, mine never did that. bad gaskets certainly have the ability to cause poor running. as do the icm. you try cleaning the tabs on the icm or have access to one that you could swap to see if its something simple? sometimes junk yards will let you if you are troubleshooting something like that and if its not you can get your money back