Jerking RPM after hi rev

[Excalibur]

Hi there auto gurus.

Just want to know what could be the possible problem/s that causes this jerking RPM problem and causes the (almost) shutdown of engine after hi rev either on highways or even at a standstill??

car details:
'97 Nissan Sentra SS
approx 140K mileage

Had a pms at speedyfix wherein i had a change oil, sparkplugs and cleaning of the MAF (?). Changed the simota ail filter recently.

The car engine doesn't sound normal when this problem occurs. Any ideas sirs/madams??

[ghosthunter]

Anyone checked the intake and intake manifold for leaks, cracks, holes, etc?

[Excalibur]

sir when i brought it to speedy almost 2 months ago, the mechanic told me that it was caused mainly by the worn out spark plugs and possibly by unclean MAF (dont know what this is??)

the RPM was at 1.4k and could not be lowered daw because the engine would eventually choke and shut off. i think it cost me more in terms of fuel consumption but it did save me from having the same problem again.

after almost 2 mos of use the RPM was normal at 1k but i noticed that after hi revs (above 3K) from say travel at C5 or edsa, the engine demonstrate said unusual noise and the jerking of the rpm when i slowed down.

as for checking of any leaks, the mechanic at speedy didnt mention anything about leaks but rather concluded that the trouble was caused by the sparkplugs and the maf.

[Excalibur]

the chances of this problem usually goes on a ratio of 2 out of 5.
3 out of 5, it goes well nman as normal.

meaning it doesnt occur everytime but when it does i am really bothered that this might cause accident for me or for other motorists near my ride at the time.

[Excalibur]

mga sirs/madams, sinumpong nnman yung jerking rpm na sakit ng ride ko kanina lang.

while having a high speed and hi rev along C5, after slowing down the rpm needle gauge went berserk again. then when i checked after i parked, we noticed that the unusual sound came from the engine or somewhere inside it. parang tunog diesel engine cya.

mukhang malayo po cya sa air intake or sa simota filter nya although i would be bringing this car to casa para ma assess cya ng husto.

any more input on what are the possible problems??
free po ba ang magpa check assess sa mga casa?

[CivicVTi]

If I may make a suggestion...put back the original air filter assembly. I have an acquaintance who drove a stock car (forgot the model, sorry). While the car exhibited no abnormal behavior, this acquaintance of mine decided to install a Simota air filter kit.

After installation, the car's behavior changed. Sometimes the rpm would rise for no reason, and then dip drastically. This was immediately after the Simota change.

After a few weeks of this, he decided to go back to the stock setup. He removed the Simota, reinstalled the factory air filter housing...and presto!
The car's behavior went back to normal. No more erratic rpm changes.

[Excalibur]

thanks for the input sir civicvti.

but this problem wasn't present when i bought the car as 2nd hand, taking into consideration that the air filter was already changed to simota kit. i only noticed this problem almost a year after. the car was running perfectly smooth before.

as assessed by the mechanic, he said that the worn out sparkplugs and the dirty maf was the cause of said abnormal behavior (jerking of the rpm).

[speed unlimited]

thanks for the input sir civicvti.

but this problem wasn't present when i bought the car as 2nd hand, taking into consideration that the air filter was already changed to simota kit. i only noticed this problem almost a year after. the car was running perfectly smooth before.

as assessed by the mechanic, he said that the worn out sparkplugs and the dirty maf was the cause of said abnormal behavior (jerking of the rpm).

Bakit hindi mo muna palitan ang sparkplug at palinis ang MAF sensor maari ring dahilan ng problema ng makina mo.

[arieslhon]

if problem still exist after replacing spark plug ang cleaning MAF, try to reset ECU and perform idle learn...

first start engine and wait to reach operating temp...
then turn off the engine and pop up the hood to locate fuse box and remove ECU fuse for about 10 secs.
after that replace the fuse and close box. start the engine and let idle for 10mins with closed hood and no electronics accessories are on.
after 10 mins. turn of the car, idle speed are not reset.
Start the car and go drive like you normally would so the PCM can relearn the fuel maps.

[t2erns]

obd2 na ba yung car, me capability ba na ma scan ito? mas maganda siguro ma read ang mga sensors para malaman ang most probable cause ng problem. remember may mga malfunctions na hindi basta mag flag ng trouble codes and check engine. i suspect a bad maf or air leak after the maf sensor and or iac issues.