Engine Stutter at high speed...HELP !!!

[323iguy]

O.k...I hope someone can help me solve this..... I will do my best to explain a weird anomally I am currently experiencing....

Whilst I am driving at high speed [ anywhere between 60 - 110kph ] .. and when I reach a constant speed the car feels jerky and jittery..... almost stuttering....however I have good constant speed and RPM's...no power loss

when I accelerate the jittering goes.... when I back off and cruise again.. the jittering/ stuttering feeling comes back.....there is no missfiring... no splattering....no hessitation......good acceleration.....no pinging/pinking...good high and low speed pull to 3500 - 4000 rpm...
it almost feels like I am driving into a strong head wind.....the cars being pulled back..... a stuttering sensation.....

What is the cause of this jittery feeling at constant speed..???

Any clues to this puzzle for me...??

Thanks for your help.!

[j123crx]

mine does that too, cruising at a constant speed and it chugs, sometimes for several minutes and then it just stops. i thought gunk in the tank-low fuel/blocked fuel injectors/water in the tank ? i put in some injection cleaner and it seemed to stop it.

[Kowalski]

change your fuel filter, and your air filter. also, does this ever happen under full throttle? it could be the tps (throttle positioning switch).

can you give us any more symptoms to work with? how does it idle? is it shakey, when you rev it in neutral does it lag and then rev up, or does it just rev up?

[323iguy]

thanks for your input.....brand new fuel and air filter just fitted...new rotor/cap/leads as well......for you information: this problem exsisted before the new parts were installed...
and yes... idle is not as smooth as before...uneven exhaust pulses..... and yes....there is a lag when I give her a rev in neutral....bit of a hesitation around 1300 - 1500 rpm...
is it vacuum leaks...????

Thanks again for your help....

[Kowalski]

yeah, sounds like a vacume leak, use propane or starting fluid or somthing and spray it arround your vacume lines and if the idle picks up you have a vacume leak. also replace any cracked hoses

[323iguy]

Thanks Kowalski,

Yesterday I removed the old crank case ventilation [ valve cover ] hose and discovered it was totally caked up with dry oil and gunk..very restricted breathing capacity....I replaced it and also cleaned all associated side vacuum t joins and splits etc..... and it has made a noticable difference...idle and start smoother....steadilly replacing all old vacuum type hoses.....will get there eventually.... :]

[Kowalski]

no problems.