shuddering!

[nghie]

hey again. I know I'm flooding the place with my threads... But i just purchased the car and have a few bugs to solve. Basically when the car is idling, in drive park or neutral, the engine shudders and the vibration can be felt through the steering wheel every five to ten seconds for a split moment. The revs drop by about one hundred during this, and then it's fine. What could be the cause of this fault? Thanks again. Dan.

[monkeys437]

Could be a misfire or you could be running on 5cyl. Id look at the plugs and leads to see if they need changing and if it continues maybe a compression test

[nghie]

indeed. Well, the plugs are out of the question. I got a new set, gapped them to one point five mill. Along with oil and oil filter change. The previous plugs showed no sign of leaning out. They Had an even black coat. With the leads though, if i run a resistance test on them, what would be an acceptable ohm reading of each lead? To add, what is a good cylinder compression reading?

[wortus]

The short leads I think 10kohm max and the long ones 17kohm max. i had a lead open circuit and the car idled badly in the end. It also shuddered and I felt a jolt from under the car when I loaded the motor slightly.

[nemesis_adrasteia]

i would also be checking the coil packs

[wortus]

Also check all the wiring on the engine especially the large plug that connects to the DFI module under the coils, it may be getting a bit loose or corroded.

[nghie]

Thanks guys, for the input.

You've given me an awesome place to start; i'll slowly chip away at the problem. Hopefully, it's not something really terminal.

Cheers, i'll let you know as I go along.

Dan.