RPM drops off intermittently. Is this a Carburetor Problem

[goldencoil]

When I start off the engine in the morning, the RPM goes to 1000 RPM then drops off to zero. To solve this, i keep on start my engine and step on the accelerator till I get to 2000 - 3000 RPM before it goes to the normal reading which is 900 RPM. Let it be noted, that I do this solution for 5 to 10 times before it fixes itself.

When I turn on the AC, there are times that it suddenly drops off to ZERO again. What I do is to step off the accelerator real hard ( while in neutral) before turning the AC.

My father and I brought this to a mechanic and we replaced several parts like High Tension Wires , Spark Plugs, PC Valve, Condenser ( sa carburetor ata to) kasi may mga nakitang palyado. After this, the problem was resolved but it came back after a day.

Ngayon, litong lito na rin yung mechanic. Nde na rin nya alam ang gagawin. Let it be known that the carburetor has been overhauled already. Temporary fix namin is to increase the idling. Ngayon, it's set to 1500 RPM at nagiging 1200 RPM when I switch the AC. Ang nakakainis nga eh minsan, bumababa nang 600 RPM pa din at parang gusto pa ring mamatay nang makina.

My ride is a Toyota Corolla '90 XL5

Here are my questions:
Q1. What can be other reasons for this problem?
Q2. I want to try another mechanic na expert sa ganito especially for Toyota Cars. May maire-recommend ba kayo? I live in Taguig so convenient sana kung malapit lang dito like Makati , Pasig and Pasay.

I would really appreciate your inputs guys.

[zeagle]

May iidle up or vacuum switching valve ba yan? If there is have it checked including the vacuum hoses.

[badkuk]

amoy gas ba ung exhaust? di kaya ung air filter, o marumi na carburetor?

[goldencoil]

badkuk and zeagle: Nakalimutan ko rin palang ilagay na may idle up switch ito at nagpalit na kami nang air filter.

May nakita akong similar post ngayon ngayon lang na binanggit yung diaphragm at mga hose.

Itsi check din namin yung vacuum hose. Saan ba makikta yun?

zeagle, pareho lang ba yung idle up at vacuum switch valve?

[boydapa]

ganyan din problem ko dati

so assuming na ok ang makina at walang deperentsa

gawin mo bumili ka ng surplus na carb tpos(lilinisin yan at irerestore)ipakabit mo sa kamuning i can recommend u to him

edi solb!

[zeagle]

Itsi check din namin yung vacuum hose. Saan ba makikta yun?

zeagle, pareho lang ba yung idle up at vacuum switch valve?

Dude pareho function nyan. Yung idle up usually mechanically connected sa carburator. Yung VSV by vacuum hose. Yung vacuum hose, rubber hose na maliit yan connected to the VSV. Pag may leak, VSV will not function properly.

[goldencoil]

Dude pareho function nyan. Yung idle up usually mechanically connected sa carburator. Yung VSV by vacuum hose. Yung vacuum hose, rubber hose na maliit yan connected to the VSV. Pag may leak, VSV will not function properly.

Ah ok. Nde ba kayang ako na lang ang mag check nun like visually checking kung may leak. Ano ba symptom pag may leak yung hose na yun? Tsaka san ba banda nakikita yun?

Isa pa pala, may mare recommend ka bang shop na pwede kong pagdalhan?

[Shadetree MKNX]

It could be the thermotime switch that controls the EGR valve. Next time you start the engine cold, remove the vacuum hoses between the carb and the cylinder head and plug the exposed grommets temporarily with some tape. Start the car and see if the problem disappears.

[gwapito69]

check mo yung vacuum hoses mo baka may butas o crack kaya ganun

[w3stic3]

yung car ko din nag ddrop lagi yung rpm, ive found out na may nawalang pin sa carb ko that i eventually replaced, pero bumalik ulit yung problem! any ideas kung san makakabili ng carburaetor repair kit? oto ko honda lx 93 (ph12 engine)