RPM goes down
Asked by shumanhvc Dec 24, 2017 at 07:11 AM about the 2004 Toyota Premio Sedan
Question type: Maintenance & Repair
I have a Toyota Premio 2004 which had a run of 130,000 km. the engine
have been replaced two and half years ago. now the engine is performing so
bad recently. i checked for everything. Throttle body is ok, plugs and coils
are ok also, valve clearence in ok, pressure of the four cylinder is ok alsso.
but still the rpm of my car at drive goes down to 500-550 and vibrates a lot. i
tried to increase the rpm from throttle body even to 1600 but it goes down to
500 automatically. no way to resolve the issue. the car also stops when
running slow or trying to turn right or left. i cleaned th throttle body even
changed, but no change. engine mounting are ok. when turn on the ac the
rpm does not increase a lot in this situation. 50 increases. can you help me
out, i am fed up with this car for the last four and half years, can not sell
either due to some financial crisis.
10 Answers
beatupchevy answered 6 years ago
have you scanned for codes ? tested sensors ? do you have the equipment for real time data ? It's run by a computer and needs to be diagnosed unless you want to go broke replacing parts , even the random mechanics that I hear about on these pages don't understand these basic principles , look for motor to body grounds or see if injectors are firing normally , some vehicles are particular about proper fuel pressure and spark just having them won't always do
You don't mention how many miles you racked up on this engine, if it's a lot then it can be any number of problems or just wear and tear. You mention "pressure of the four cylinder is ok", did you run a compression test? All cylinders are within 10% of each other? How is the timing? Focus on the basic stuff before tearing into an engine, like Beatupchevy suggests, check fuel pressure and clean sensors, check throttle position sensor. Check/clean PCV, if clogged it can force blowby gases into throttle plate. Pop it off and clean it, takes all of 5 seconds.
beatupchevy answered 6 years ago
EGR ? ? who knows , nothing easy about it , loose broken vacuum lines , crappy gas
Well no vacuum leak found. This engine ran about 24000 km at my end. This is a reconditiined engine. However thanks a lot both of you for trying to help me out so promptly. I will go to the workshop tomorrow and suggest them as per your suggestion. Thanks again. Will inform.
I ran a cylinder test also got more than 10 bar in each one. And within 10%.
yes i went to a professional workshop. but they could not solve it either. they say, rpm will come to 600 at drive to whatever extent you increase it from throttle body. but at 600 the car jerks and vibrates a lot. they tested the plugs and coils again, for vacuum leak but found no problem.
no codes found, the rpm of the engine is now at 1000 (app) and reducing day by day. i dont get it. its increased from throttle body to 1600 (8 no screw).
