Unsteady rev Needle???

2002 Mazda Premacy Problem

The Problem

Avatar Lif
Joined: 6 years ago | Fixes: 1 | Profile
About

The car injection nozzles has been taken out to be examined,and they were fine so put back, the car usually starts perfectly without problems, but since the nozzle checks, the car shook unsteadily at idle with unsteady rev needle. The car has been thoroughly checked for hose connections and leaks, MAF passage leaks, and electrical plug cables, everything seems okay. At start however, is unusual, as the rev needle always jumps up to 1.5-2000 rev/min then shakes unsteadily drops to 8-900 rev/min and stays there, unsteadily, and the engine shakes. At idle when the needle drops lower as if to stall, the engine shook harder, and the confusingly the needle jumps back up to 1.5-2000 rev/min again and then drops lower again to 8-900 rev/min, and this carries on and on until it is in motion that's when everything seems fine as the needle is steady and the acceleration is just fine. At stationary with gears D or R on (brakes depressed), the car shook harder and sometimes stalls, except when the gear is switched to N at idle, the needle unsteadily shakes between 8-900 rev/min.

Could someone please help on this?
all the best!
Thanks


Car Mazda Premacy
Variant 1.8
Model Year 2002
Category Running Rough, Starting & Power Loss
All Mazda Premacy Problems

Solution

Avatar whittingehame
Joined: 9 years ago | Fixes: 12,036 | Profile

If you are sure there are no vac hoses or air leaks , check / clean idle air control valve and throttle body .

Solution

Avatar roverman
Joined: 6 years ago | Fixes: 392 | Profile

i put in other post about checking compressions on engine if one is low doing injectors and throttle body etc is a waste of time so i would check compressions first if ok check the valve timeing is correct i seem to remember on these engines that the belt tensioner relies on a spring to hold tension on belt if this spring has become weak valve timing can jump hope this helps you

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