sierra flat spot and massive headshakes

[razza101]

ok i have a 84 sierra 1.3,
problem 1, massive flat spot that starts at about 1700 revs then dies and comes back to life at around 2500 revs i cannot find what is wrong with it, and ideas and thoughts would help.
problem2, when it finally kicks back into shape and start to get up a bit of speed it gets massive headshakes at around 65kmhs it gets so bad i cannot hold onto the wheel i have to slow down to hold back on.
i have no mods on the car as of yet not even tyres there just road tyres so yea again any ideas would help

[PJ.zook]

Prob one i cant be of much help, but prob two sounds like death wobbles. Do a search for 'death wobble' and you will find plenty of threads about the problem, it happens to most of us at some time. It is unusual that its doing it to you with standard tyres or lift though.

[alien]

flat spot will probably be the carby - most likely needs a rebuild, maybe just has clogged jets.

wobbles are hard - mud in the rim, bulge in tyre, tcase or engine mounts, driveshafts flogged out etc etc

[Kitika]

Could be spark plug leads on the way out causing the flat spot. Otherwise it could be carby but depends if it chugs or misses.

[Turbo Tonka]

i put my death wobbles down to extended shackles,lift kit and worn bearings.

Am about to recheck n replace wheel bearing to try help mine.It can be a bit scary so possibly start looking there??

[mr green]

i also had the death wobbles in a standard zook. i tightened wheel bearings and added a stabilizer ( mine was torn off) and it was gone. since then i have changed the steering box and removed the stabilizer ( went to power steer) and now it is just starting to get the shimmy. i will be refitting the stabilizer again soon and i'll check the bearings again, but will do it in 2 goes to find out which one is causing it

[Turbo Tonka]

then you will come round and do mine,thanks jas

Last time i had mine half acceptable was after nipping up the bearings.So im pretty confident new ones with some fresh grease will be the GO

[alien]

dont forget the stablizer will mask vibes... its not addressing the issue, just covering it up =)

on the flat spot - when my leads were stuffed i had flat spots, but it backfired alot and idle hunted all over the place - thats usually a sign the auto choke is stuffed and carby needs a rebuild, but new leads did fix that. Worth looking into for sure.

[lucifer48]

Hi Razza, that flat spot is a carby problem, its an easy fix but will take a little explaining.
PM me your number and I will tell you how to fix it.

Cheers Louie

[bones60]

i also hav the same problem with the flat spot and hav had a carbe kit put through mine which helped a little but still does it

[topdown]

Have a few instances of flat spots.

First time it was the dizzy, replaced the rotor and cap and it was all good.

Second time I needed a new coil.

Third time it was one of the spark leads, replaced that and haven't had any problems since.

As for the auto choke it's a useless item on those carbs. The car will start without it no probs. Just remove the butterfly or wedge it fully open and your idle probs will disappear.

It was like a new car once I took the choke out.

[TasZook]

i had problems with a flat spot/dying when you accelerated then it would jump to life. ran carby cleaner thru it 2 tanks in a row and its never driven so well. been about 5000 kms since and still going strong