960: Bad Vibes?

Ugh. Have another issue I've been wringing hands over on-and-off for a while now...

More often than not as of late, there's a nasty vibration which plagues my '95 mill starting @ around 2K, in neutral or under load. Been through everything I can think of; and over the past few months I've ruled out injectors, plugs/coils, MAF, vacuum issues, uneven compression (sticking valve(s) etc), mounts, rail pressure. EGR factored out. Looked at a 1-1-2 code issue/MIL* a few months ago, but that was covered in one of the bulletins as nothing more than an false-alarm annoyance associated with the old OBDI. No other codes at all, and it's not been a constant malady; so a mechanical imbalance doesn't seem likely. Idle good, starts quick. Fuel econ is always good, but power really stinks when it's misbehaving. Getting seriously pissed-off driving a luxury version of the early Ford Escort...

Gotta know what might be at play here before I push anything more serious into this car. If the old brute has some sort of "find the bad Christmas tree light" electronic plague, I may just have to let it buzz and drag it's tail while I make other plans moving forward.

Anyone else have this type of issue???

Thanks a bunch --


*Problem was sporadically in evidence well before 1-1-2 was ever thrown.

i had a real similar issue a while back with my 97 960... would be fine and then stumble driving down the road while losing power, sometimes even dying all together. turned out to be some loose grounds for the computer or ignition on the driver side under the intake mani by the motor mount. tightened the grounds and has been flawless ever since.
hope it helps

Performance and suspension?

Coil Harness?

@Stevenl & HiSPL:
Thanks for the input. This whole situation has been really queer, perhaps complicated by the complete lack of codes. Just came back from a run with it just a minute ago: buzzrumble, buzzrumble. It's so bad sometimes, it even sets up a resonance with the rest of the driveline to create a slowly-sweeping standing wave which moves across the car from front to rear...

@vincentzgagnon: Glad to meet you!

No, it's not running xPSI boost on NOX @ n:1 CR; but I really need to get this particular gremlin nailed down before I can entertain anything beyond grocery-getting for the car. In consideration of the massively complex nature of these vehicles' electromechanical implementations, this type of thing could conceivably strike anyone's whiteblock in any state of build; therefore, I thought it could be of universal interest to the community.

This, coupled with the cutting-edge and seasoned savvy this board has to offer, I decided to nestle the post here.

Hope I didn't offend anyone...



At any rate, thanks once again; and have a great New Year --

curiousCat said:

@Stevenl & HiSPL:
Thanks for the input. This whole situation has been really queer, perhaps complicated by the complete lack of codes. Just came back from a run with it just a minute ago: buzzrumble, buzzrumble. It's so bad sometimes, it even sets up a resonance with the rest of the driveline to create a slowly-sweeping standing wave which moves across the car from front to rear...

@vincentzgagnon: Glad to meet you!

No, it's not running xPSI boost on NOX @ n:1 CR; but I really need to get this particular gremlin nailed down before I can entertain anything beyond grocery-getting for the car. In consideration of the massively complex nature of these vehicles' electromechanical implementations, this type of thing could conceivably strike anyone's whiteblock in any state of build; therefore, I thought it could be of universal interest to the community.

This, coupled with the cutting-edge and seasoned savvy this board has to offer, I decided to nestle the post here.

Hope I didn't offend anyone...



At any rate, thanks once again; and have a great New Year --

Click to expand...

my dads 95 960 did the same thing, never could figure it out what was causing a weird resonance/vibration that would randomly happen, causing quite a racket, though it was mainly 50-65mph range it would rear its head

They got tired of it and traded in during cash for clunkers

I had a few misfire codes when mine acted up

The rear of the driveshaft has a CV joint instead of a U-Joint and they go bad, causing very strange vibrations and noises, but only when you're moving.

Sounds like a misfire (coils love to go bad) or a driveline vibration like a bad u-joint (some have a rear CV joint) or a bad center support bearing.

More likely a misfire since it happens in neutral and doesn't have any power. Could be a power stage going bad or the ignition harness going bad too. These cars have two separate banks and two power stages for ignition.

There were updated coils at some point. I got the later ones for my car from a S90.

Thanks, everyone, for the great input. Glad I'm not the only one out here who's run into this type of issue.

Hmmm. All plugs were replaced. Wiring looked good; no climate rot or other readily apparent issues. Coil packs were all checked, and came up OK via DMM. Not saying there isn't some sort of failure occurring coilwise during operation (would love to see this secondary circuit on the screen of an old Sun Scope ), but it'd probably need to be more than one cylinder malfunctioning (and then returning to normal) simultaneously to vibrate things the way I've been experiencing. Also, wouldn't we be seeing a misfire code if the coil(s) were going out to lunch? It's been getting worse over at least a couple of OCIs; and plug color is consistent and normal(!)

On that point, wouldn't there also be some sort of code thrown for power stage issues? This, however, might fit the MO better in consideration of the overall "buzz" vibration rate (beginning to wonder)...

You'd almost definitely get misfire codes for bad coils. I did before I replaced all my coils. I rarely hear of the power stages going bad, but they certainly could. They're mounted on the front and back of the intake manifold, if you're looking for them.