1997 Q45t Engine Shudder

[smalcom]

I have a 97 Q45t with 85,000 miles that has developed an intermittent engine shudder when sitting at a traffic light. It happens irregularly, and feels as though the car is going to stall. It shudders once and then runs fine. I cannot identify any pattern to this. There are no warning lights displayed when the car does this.

I have recently had the valve cover gaskets and spark plugs replaced.

Does this sound like a major repair? I am not mechanically inclined, and do not have a place to work on the car if I could. The car will have to go to a mechanic to be fixed.

Any ides as to what could be wrong?

[oldmako]

Could be your blinker fluid, or most anything else. Hard to say.

If it were mine, first thing I'd do is run some quality fuel system cleaner through it along with a tank full of fresh, quality gas. Replace your fuel filter if it's less than a year old. Todays E fuels pretty much suck. Might not be a bad idea to add some ISO heet as well.

Lots of discussion here regarding fuel additives. BG44k used to be the sooper-jizz, but a recent change to it's formulation has caused much angst, consternation and trepidation among the Qmasses. Seems to me that "Redline" is the new jizz-du-jour but from my comfy chair I have no idea.

Shoot some MAF cleaner on your MAF.

There are some here who will tell you that it's time to douche the entire intake and all the associated plumbing and bits. To spend a grand on new hoses, gaskets. To take your car out of commission for two days to get it all done. To lay bare the top of the engine and find every little piece of crud and carbon and sanitize. He's currently on sabbatical.

That's a lot of work, with no guarantees of a fix and opens you up to large exposure to other problems. Try the easy stuff first.

Bad gas is almost as bad as bad juju. Best of luck in the rectification or your rides anomaly.

[trajanH]

My 97 q45 car overheated and I replaced the radiator and then it started to do that also. At a traffic light I get a tiny little bump sometimes. Its like a cylinder has blipped off. I am going to run a diagnostic with OBD Scan Tech to see if I can come up with anything.

[paranoidjack]

This is the famous fgy33 "stumble."

We've all had it it seems, although for some of us it has gone mostly away (me) without replacing any of the suspected components (coilpacks).

Do a search for stumble and you'll find tons of information on it - this has been posted many times before.

[elwesso]

I would do some of the advice that oldmako suggested.. Thats a good place to start, and if your not getting a CEL (which coils typically give CEL's) then i'd go that route.