my car wants to stall after starting

[94cylcamry]

Hey all, 94 Camry LE Auto with 159,000 miles.

I've got two separate starting problems, I'm wondering if anyone could shed some light on either. They've both started within the last month or two, when it's started getting cooler out, though I don't know if that is related or not.

#1, sometimes when I start the car, I hear a...like jamming metal mechanical noise from under the hood. It's sort of hard to describe...it's usually right after I let off the key because the engine is started. When the sharp jamming sound comes, the rpm goes from normal quick down to like 400, like something caught or jammed, then goes back up to the normal rpm without me interfering. Happens a couple times a week, doesn't affect starting, is just sort of...I don't know. It hasn't caused any problems yet, maybe it will in the future.

#2, sometimes when I start the car, the idle rpm goes down incredibly low, and the car acts like it wants to stall, but never quite gets there. Instead the car just vibrates as the engine rpm flutters slightly like vroom VROOM vroom VROOM vroom VROOM. I hope you know what I mean. Very low rpm to slightly higher back to very low, to slightly higher. Usually I give it a little gas, and it just goes back to idling normally. This is not at all limited to when the car was cold, in fact the first time it hapenned, the car was completely warmed up. But it happens when cold and when warm.

If anyone could shed any light on this, it'd be great. None of these are really earth shattering problems, I'm just curious if there's anything I can or should be doing to fix them.

Thanks!

[toyomoho]

You may have two separate issues.

Determine if the starter motor gear is failing to retract after the engine starts up and causing the engine to drag. Or a bearing on the alt or PS is binding at starter up. Or a bad water pump bearing.

The hunting idle could be due to a MAP sensor or IAC valve.

[94cylcamry]

Where is the MAP sensor? How can I tell if I have an MAP or an MAF sensor? I thought I had the MAF. And the IAC...I guess I can spray some seafoam down there and see if it helps at all..

As for the other things...I'm not sure how you would tell if any of those were hapenning...

[toyomoho]

The 4 cylinder has a MAP. It should be a small plastic box bolted to the center of the firewall with a small hose coming from it.

Do a TN search as there have post on how to clean the IAC on this engine.

You can remove the starter and look at the teeth. Rotate the engine by hand using the crank bolt and look at the ring gear teeth. If the teeth look damaged the starter may not be retracting after startup.

Remove the accessory belt an turn the alt and AC clutch by hand, feel for binding. Also the PS pump.

One other thing to check even though it is cold is if using the AC, the compressor is making the noise.

[Kep]

^+1

A cold engine bogging down also suggests a failing EGR system. This can be cleaned or replaced. I think this is especially suspicious if it doesn't happen when you start a warm engine.

Initial checking of the other items that Toyomoho mentioned is largely by listening while someone else starts the car. Often you can get a good idea of which area the sound is generated from.

I expect that a failing ECT sensor might also cause this kind of symptom.

The 3SFE engines were the last 4 cyl to use a MAF sensor (on the air filter cover).

Kep

[94cylcamry]

Wow, thanks for the info guys!

I hope it's not the EGR system, I hear that's hard to get to and expensive to replace. However, the problem happens randomly and without warning, and the engine has been both hot and completely cold when this has hapenned. Hopefully that rules out EGR troubles to an extent.

I'll search on how to clean the IAC valve, though sounds like the easiest of things you suggested, so I may start there.

Not familiar with the ECT sensor...and would the MAP sensor need cleaned or replaced? I've never seen it before.

As for the starter...there's just a few bolts holding that on, right? I just pop it off and look at the teeth on it, and then the gear it connects to? I've never seen or used the crank bolt, but hopefully I'll see it when the time comes? Same goes for the belts...and the accessory belt...rotating those things wouldn't have anything to do with timing right? That's just the timing belt? And when I rotate the things mentioned...they should just rotate completely freely?

Thanks very much!