here's the problem: car starts fine when cold. When fully warmed up, if i stop to go to the store or something, and then start it after like 20 - 30 minutes it will start and the idle will be fluctuating between 800 and 400 for a few minutes and then even out. sometimes it will actually start up and die immediately, in which case i can save it by giving it gas for a few seconds and then it's fine.
what i've done so far: plugs (NGK), wires, cap, rotor, fuel filter (toyota), (checked air filter. still clean), tried cleaning the throttle body and IAC with some deep creep spray while on the car (not much effect).
today the car was better. i also observed a few things that might make a difference.
i know the target idle in park or neutral should be 750 rpm +/- 50 rpm. today the car started great when cold. held 800 rpm for a few minutes then started going closer to 600 when stopped and with foot on brake. when it's close to 800 it feels great with no vibrations. i noticed when i was stopped on a hill waiting for a light, i took my foot off the brakes and the idle went up to normal (like 750 rpm) and the shaking stopped. to me this kind of sounds more and more like the idle air control valve but the part costs a pretty penny and i don't want to replace it haphazardly. could it be a vacuum problem?
just spray some carb cleaner in there the IAC that is if you take of the air inlet to tube to your throttle body you will notice a small hole on the inside of the throttle body towards the bottom. Spray some carb cleaner in there with the car off let it sit for 5 mintues allows it to dry out so you can start it and see if it improves.
The EGR valve can also cause that problem, which can also be cleaned with carb cleaner but needs to be removed first.
what i've done since: fuel filter, fuel pump and strainer (it was making loud noise. good now!), cleaned throttle body and it's vacuum ports (while on car), EGR VSV, and replaced all the vacuum hoses i could get to (all but the ones that run behind the engine, near the firewall) to try and rule out vacuum leaks (still have to spray intake manifold and throttle body to intake gasket). problem is still present, just not as severe as it was.
Here are some areas i still suspect:
1) EGR valve and cross-over pipe: Probably gunked up. new one costs over $200. gonna clean it.
2) IAC valve: probably deep crud inside. jumped the two terminals to actuate the idle and it responded correctly.
3) Fuel pressure regulator: can't confirm fuel pressure because my tester didn't come with the toyota fitting, but might as well since i replaced just about everything else on the fuel system.
4) spark plugs and wires: plugs are the non-platinum version of the recommended plugs. does this make a difference? the wires are non-NGK, non-name brand and i doubt their integrity. will ohm them tomorrow.
5)coil and distributor: when i checked the coil, primary resistance was 0.6 and i got nothing for secondary resistance. manual says i need to check air gap and something else.
6) possible vacuum leaks: i don't hear anything, but i know leaks could cause this problem too. will replace hoses and check gaskets.
7) timing belt: previous owner mentioned that they hadn't had it replaced before selling the car.
8) valve adjustment: uncertain if this was ever done.
well that's all my thoughts about it. tell me what you think!
Last edited by GTcelica22; 05-20-2011 at 12:24 AM.
after performing the work mentioned above, when started up in park or neutral, it will idle at 800 rpm religiously. that's good. however, once i put it in any gear (reverse, drive, etc..) it will go down to around 700, 650 rpm even. it's worse with the A/C on. with ac on and in drive, it will go down to 600 rpm. it will sometimes come up to a normal level but then go back down again and shake like it's going to die.
did a LOT of work today! i took off and cleaned the throttle body, IAC valve, EGR valve, crossover pipe, temperature sensor, what i could reach of the intake manifold, and replaced two more vacuum hoses (they both connected to the EGR VSV). i also disconnected the battery to reset the computer for the repairs. it idles real a little better in gear, but turn the a/c on while in gear and it dives down to 600. if you turn on the ac when in park or neutral it doesn't go down that far. it surged once and it was very minute, like by 25-50 rpm.
i also tested a lot of things too. throttle position sensor passed with flying colors, IAC valve opened and closed when i jumped the pins, it's resistance on each side was 22 ohms at 80 degrees (yeah it was hot today). The manual says between 19.3 to 22.3 ohms at 68 degrees is good.
put vacuum on the EGR valve after cleaning and the diaphragm moves good. held vacuum good too.
i ohm'd a spark plug wire that was easy to get to. i measured only .986 K ohms. limit is 25 ohms.
Now I can't be certain cus when it comes to an ignition issue, you're screwed.
If you've already changed your igniter, plugs, wires, coil, distributor cap and rotor...DO NOT hesitate on focusing on the actual distributor itself.
This is what happened with me. I also got it scanned by my mechanic, the 3 codes that appeared were related to having a shitty distributor.
My baby keeps dying on me anytime it's being driven for too long, heated as regular. The patterns were VERY unpredictable unless focused on very deeply, a relation was possible to see.
I was assuming it was a shitty coil and wires. My baby started getting WORSE the past 2 weeks of hot humid weather. But it wasn't acting up as bad in the rain..this confused me. I went and bought a wet dry spray to spray my wires and battery..i convinced myself it helped start my car when it wouldn't after spraying it on and trying some attempts, or waiting it out 15 min..
The actual issue was that the heat makes a shitty distributor act up 19283498 times worse, had nothing to do with humidity/moist. It's not a matter of timing/predictions..when it comes to a bad distributor, it all depends on what IT 'FEELS' like doing lol. It will either never start, or will start but die on you after using it up on and off, or will start but die on you instantly. Any possible prediction has happened with me.
I didn't have as much as a rough idle though. But judging by your undescriptive symptoms, it can seem like it'd be a bad distributor.
Your best and safest bet is to get it scanned before going along and changing 80989 parts that wasn't really necessary. You don't have to rely on dealerships for that, some shops do carry a scanner. Know your people, keep some hookups, goodluck!
Hey thanks for commenting! It's funny you mention distributor because I checked it today and the pick up coil tested bad! Ignition coil was good on primary and secondaries, plug wires were in spec too. I DID however find that my air intake had deteriorated an developed cracks and even a hole at the flex point in the middle. I had no substitute for it so I used electrical tape and it seals well. Not sure if it matters on a MAP sensor system but I wasn't going to leave it like that. So come Monday I will be purchasing a dizzy and will be letting u all know how it goes.
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