Bucking when slowing down or stopping

[reddo_tuner]

ok, recently got my car back from the Mech, change out suspension. First thing is I hear a knocking noise when i hit a depression, not like the shock, more like when the care sways, or I am stopping and I pull aside, i hear it.

It sounds like a rubber or buffer needs repairing. Another problem that has seem to have gotten worse is the bucking when slowing down, I constantly have to be going from drive to nuetral when iam at a traffic light. when the AC comes on, the rpm goes to 900, no bucking, but in between the ac blowing cold air in, it reverts to bucking, rpm is at about 500. I had changed the mounts and the issue wasnt so bad, could my mounts be going already?

Could my fuel filter need changing?
Could my gas tank need checking?
my fuel lines?

[praise]

What mechanic is that? Exactly what car are you speaking about? And what suspension parts was replaced?
The knocking could be because of several reasons: something slack, broken, worn or incorrectly installed. Check links, shock buffer, rack ends, steerings ends and ball joints.
Concerning the bucking, your injectors, spark plugs, plug wire or trottle body needs replacing or servicing. Yes it is also wise to change both your air and fuel filter as well. Your step up motor could be sticking, hence the reason the rpm drops.

[gt4tified]

Check a/c idle up valve.

[AllTrac]

as ralph said also check for vac leaks

[lastminuteaudio]

did he interfere wid ur TPS?

[ramishrrr]

Possibly a bad crank position sensor

[haydn28]

reddo start with the simplest stuff first:

1.clean out the throttle body with some gumsolve.
2. check to see if the idle screw slack , remove it and use some thread seal on it....
both myself and A172 had this problem in Camden (4efte fault?) .

report back when yuh done

[Hibrydsoul]

I know this thread is old but I'm getting the same bucking problem.... When I start the car first thing in the morning the rpm drops considerably and the engine behaves like it wants to cut off.... It'll eventually correct itself after awhile. 2) Whenever I'm in traffic and a/c on and in drive.... the car will idle and ever so often I will get a buck or drop in engine rev which sometimes causes my turbo timer to reset. It's quite annoying and 3) I accelerate and ever so often I'll experience something like a backfiring during said acceleration. What I've tried so far was changed the dizzy timing and changed spark plugs wires. Strange thing tho it never happened till I tune up recently so I'm wondering if its the spark plugs.

[xtech]

Sounds like u suffering from something electrical. Check for shorts In your main power lines from alternator to battery....

[Hibrydsoul]

Looks like I may have to visit the electrician..... but before I do that, I realized that the engine check light was never wired..... is there anyway possible I can still check for error codes??????

[Hibrydsoul]

So I switched out the idle air control valve solenoid (17630-11050) as well as the map sensor aka turbo pressure sensor assembly (89420-10020). The car will idle fine at first and then start to idle low and sometimes the idle picks up and drops. The car still acts up when I press heavy on the x while driving as though its suffering for gas. So I'm going to check the fuel pump and see if its the problem. I know its not the dizzy at least it shouldn't be but someone said to change the plugs (I use NGK BKR7EIX spark plugs). But I would really like to know is there any alternatives to check for engine error codes if the engine check light was never wired?

[gt4tified]

After you check your plugs, check the gap in the distributor, as well as your coil. A good scan tool should work.....as long as the diagnostic port is still there in the wiring harness.

[Hibrydsoul]

Hm in need of an obd1 scan tool. Anyone has one? *fingers crossed* that said diagnostic port was wired in

[outrider]

http://www.troublecodes.net/Toyota/

[Hibrydsoul]

This would come in useful had the engine check light been wired.

[Hibrydsoul]

Hmmm, could a loose valve cover cause idle issues?

[Hibrydsoul]

Nope..... I'm stumped.... Gotta call Faizool.

[Hibrydsoul]

so what would cause d engine idle to drop really low on a cold start and then it'll pick up afterwards???

[Hook]

Fuel metering issues would give those problems, especially the idle issue, if the idle air mixture is too rich on cold start. Sometimes you can barely smell a bit of unburnt fuel in the exhaust, but it's rich enough for the ECU to have to re-calibrate and hunt for idle every time you cold start. Backfiring on acceleration or when you let off the gas while driving is also a symptom of overfueling.

The MAF guys fix thing pretty easily by messing with the Idle Air bypass screw on the MAF or opening it and "clicking" the cog, but it really only goes awry when you interfere with the MAF anyway.
I'm not experienced in MAP tweaking, but things like coolant temperature sensor, vacuum leaks to the MAP sensor, intake air temperature sensor and the oxygen sensor can affect this.
I see you already started changing parts. Remember to reset the ECU when you make changes to the sensors.

[Hibrydsoul]

I've found the cuplrit and I'm now in need of a replacement of same. It being the cold start valve located on the throttle body. Apparently its not wise to spray throttle body cleaner in the throttle body as said cleaner affects the wax thats in the cold start valve. Does anyone know where I can source one or how I can repair the one I have or the part number for same?????

[outrider]

cold start valve?......is that the same as the "idle control valve"?

[Hibrydsoul]

No, its the component just below the air intake of the manifold, I'll try getting some pics.

[Hibrydsoul]

This is the best I can find on the internet..... its the part below with the red circle on it.

[Hibrydsoul]

So I found a throttle body, going swap it out and see if that fixes the problem if not, Im out some more money and Im running out of ideas/solutions. #fallingoutoflovewithStarcel.

[Hibrydsoul]

Adding insult to injury, apart from my rough idle, my dizzy has to be almost all d way advance for the car to function "normally", which I'm told shouldn't be. I'm thinking of buying a 4efe and change engine oui.

[Ted_v2]

Nah, Dont change the engine. Trouble shoot the problems.

[Hibrydsoul]

I'm troubleshooting, i need the part numbers for the the different sensors attached to said engine, also contact numbers for an 4efte specialized mechanic hopefully in the east/west corridor or central preferably no further than freeport. So far I've attained an extra throttle body water pump map sensor idle air control valve and some other parts. *rolls eyes* I just want my car back.

[Hibrydsoul]

Ok so new development...... I went to my electrician today (something I should have done from the beginning) got my CEL wired and the return on tapping TE1 to E1 revealed that all is okay with the engine which is good but I spent all that frigging money which I could have saved, but say what.... never hurts to have spare parts the problem has to be my fuel? :crossfingers:

[Hook]

Is the idle issue still there?

[Hibrydsoul]

Yea, its still there and what the electrician told me is that he suspects its either the fuel pump or the regulator giving trouble.... Or the coilpack.