Crazy Idle?????

[SamoPrd1979]

Ok I did my research on the site before I posted this and I've seen the similar question asked but never answered. Everyone gives there opioin and some sound good but I need the right answer here. This is life and death now either the life or death of my Grand Am. My wife has had it in the last 3 months I've put over 1000$ in this car not including my sound system and paint job.

Ok well about 2 weeks ago my car stated reving up and down when I'm at stop lights and after the car has been running for a while. It goes from 0rpm to 3000 and up and down like a freakin yo yo and it wont even out. So I was told by a mechanic that its a vacume leak check all your hoses so I did and I noticed that the acordion hose connecting the air filter to the throtle body was kinda loose. After fixing that problem it seemed to go away only for a few days. So now it comes back I check the hose again this time its melted on the bottom half. So I orded a new one put it on still no solution and then a mechanic told my to clean the throtle body screen with some throtle body cleaner and a rag. Did that and nothing. Well something my catalytk (spelling wrong) went out and I had to have that replaced.

Now I'm sitting here on the computer on my favorite website for my car seaching my ass off for a solution. My car is currently being inspected to find out what the problem is. The mechanic told me that the plugs and wires needed to be replaced, fine the car has 63k on it and hasnt had it done so fine. He also suggested and new filter in the tranny and fluid, ok then he shows me this he took of the hose for the fuel regulator and the car seemed to Idle at a regular pace. So he tells me that the regulator is bad and needs to be replaced, I say fine if you think thats the problem then go ahead. Then I come home and I'm reading all the problem and solutions on this great site and theres alot but not one of them actually helped me. I just called the mechanic to see whats goin on and he said we put all new plugs and wires and did the tranny and replaced the regulator and its still doing it. So what the F!!! I'm now going to this mechanic and I'm gonna pay him for replacing a regulator that hes said is most likely the problem and he didn't even fix anything?

Ok I read on here that it might be a bad fuel injector sticking or leaking or bad coil packs, this that and everything underneath the sun. I'm not made of money and I'm no sucker either. Will someone please give me some good advice. I'm like 5 seconds away from driving it off a cliff or having it stolen.

I failed to mention that its a 1993 Grand Am Gt 4d Sedan 3.3l V6

PLEASE HELP ME! THANKS IN ADVANCE FOR ALL ADVICE.

[rixGAphx]

Well, the most cost-effective solution is to remove the audio system and drive it off a cliff. :roll2:



Ahem.
On to helping you keep this thing:

Check the codes, using the 'paper clip jumper' method.

Stuck fuel injector or bad/failing coil will NOT cause it to speed-up, so don't look there.

There is NO reason for that intake hose to melt.
There is some major excessive heat in that region of your car that shouldn't be there, so find out what the problem is.
Maybe a clogged cat, causing significant upstream heat in the exhaust manifold (which is under that hose), or a leak in the exhaust itself.

Have you taken the car to have the cat checked?
Midas and other muffler shops can do a quick test, often for free if they're not busy:
* Put car on lift.
* Turn on engine.
* Burn 1/4 hole in exhaust pipe front of cat.
* * If engine runs better, then cat is plugged and needs replacement. Buy new cat.
* * IF no change in exhaust sound/engine smoothness, then cat is OK and technician will weld hole shut. Tip the guy $5 and know that's not your problem.

I've never had a problem with the TPS (Throttle Position Sensor), and don't know any basic tests.
But your symptoms, basically 'irratic idling' seem consistent with what I've read for a faulty TPS.

Rather than just looking for vac leaks, you can spray some 'carb cleaner' or 'statring fluid' around the intake manifold.
If there is a leak, it sucks-in the fluid and the engine smoothes-out (or runs more roughly, depending on the air-fule ratio created).
But first eliminate that excess heat, since it may be a source of ignition resulting in BOO!!

On this 12 year old car (with remarkably low milage), there are numerous rubber parts and sensors that were never expected to last this long.
It may be a whhile 'til we figure this out.

BTW, the auto tranny is one major vac user (a vac modulator at the front of the tranny), and the AC/HTR is another.
Does the erratic idle seem associated with either of these devices?

Finally, the main vac comes of the intake manifold, and works its way toward the tranny.
Under the battery, there's a black plastic vac reservoir, about the size and shape of a large mayo jar but with rounded ends.
The line from this vac bottle crosses the open space from the fender to the engine, and it's easy for this line to be pulled apart at one of the fittings.
Examine this tubing closely. The bottle itself could be cracked from a minor left-front fender collision.
(What I described is generic for my '96 3.1, yours may differ slightly or even greatly. But the vac bottle is somewhere and is served by tubes).

Good luck, I'm pullin' for you.
Remember, we're all in this together.
(TM Red Green Show) :D :D

-Rick

[rixGAphx]

After the car "...has been running for a while." is a major clue here.

When the car is started cold, the Powertrain Control Module (PCM, engine 'puter) is operating in 'open-loop' mode, that is, the 'loop' of information from the various sensors is not connected (therefore 'open' like a switch).
The PCM is only accepting data from the CKS (Crankshaft Position Sensor) relative to timing, and from the TPS.
So those two devices are OK on your car.

When the engine warms, it goes to 'closed loop' and starts acting on info from other sensors, and starts operating some things like the EGR valve.
The EGR valve in particular will affect the idle speed, and it is vacuum operated but PCM-controlled.
I'm not sure where it is on the 3.3, but on the 3.1/3.4 it's right under the throttle body. Where your exessive heat is.

When the PCM detects that one (or more) of its systems or sensors is WAY out control, it will revert to a 'limp-home' default program, which runs the engine rich to prevent damage to exhaust valves and other internal engine stuff.
Limp-home is basically the same as open-loop.
You can artificially-induce this mode by disconnecting the wires from the O2 sensor.
Try this, maybe your wife will leave the shotgun in the closet for a week or so while you discoverand solve the real underlying problem.

Good luck.
-Rick

PS: Seal the end of the O2 wires/connector with electrical tape so they don't short-out.
Don't run too long this way, since 1) the rich running will permanently damage the cat, and 2) you're also masking other symptoms that may be developing.

[Brad97GS]

The TPS can be checked by a multimeter. There should be three pins on the sensor. On my old Quad 4, the pins were set up in a sort of triangular fashion. Connect the top pin to one wire from your multimeter, and connect either of the bottom pins to the other one. It's easiest to have someone hold those in place...

Set the meter to resistance (ohms)....though I'm not sure of the range. Maybe 20k? Then turn the dial of the TPS with a screwdriver, slowly and evenly. The resistance should change (either up or down depending on which pins were connected) slowly and evenly as you turn it. If there are any spikes, dropoffs, etc, in resistance, then the sensor is bad. That is one way to test it, anyhow. :)

I would also look at the IAC (Idle Air Control) valve. They can get pretty gummed up with carbon, which makes it difficult to properly adjust the incoming air when the throttle is closed. You can clean off the carbon by taking the IAC valve out and spraying the spring with throttle body cleaner, using an old toothbrush to lightly scrape off the stuff that doesn't dissolve. Just be careful, as the spring is old and brittle! Also, spray some of that TB cleaner into the hole where the IAC valve sits, and check the O-ring around the valve to be sure it's sealing properly.

I agree with Rick, though, that the air intake hose should not be melting...

[4kQuad]

The best way I have found to find a vac leak is to spray spirts of carb cleaner on/around any thing you think my be leaking or sucking air. Spray along the air intake and the exhaust. I'll bet from what I read there is a crack in the exhaust manifold under the spot the keeps melting.The HOT exhaust leaking out a hole in that area is also the vac-leak.

ALSO carb cleaner burns so be careful using it. If it finds a leak as you spray little amounts at a time on places, The motor RPM will change. In most cases it tends to cough and studder. If you can make it miss or cough you have found the area to search in.

Even loose bolts connecting to the throttle body can let air in.
Rubber hoses are most often the problem, cracks or small rips, or just pulled off something.

[antoniobanderas]

it sound like a bad oxygen sensor i have same year car and it acts like your when oxygen sensor is going bad ,change it and see ,its cheap part only around 25 bucks

[SamoPrd1979]

i changed the fuel filter and it stopped, but know my car sometimes idles around 2000rpms and as high as 3000rpms but it levels out and its not a problem really, thanks for all your help.

[Jeremy321]

I have a 92 with the 3.3 v6 and my car does the same thing. i have replaced the tps and that stoped a high idle problem but the wierd low then high idle still was there i have advanced auto at school so i took it in and hooked the teck 1 (gm scanner) up and looked at the recently stored codes and it came up with "low TCP voltage" so ya yours is most probablythe same thing....

[homerjoy1973]

I had the same problem with my 97 gt 3.1.The idling problem went on for about a year especially after car was warm been shut off for awhile,replaced egr ,tps,o2 sensor checked for vacuum leaks and nothing until about a month ago.I Replaced plugs with bosch platinum 4 and wires with bosch platinum wire set,problem fixed. GO FIGURE.Car runs better than ever.

[Jeremy321]

well see on my 92 it does it only when its in park so when it starts up i just throw the thing in nuetral and set the parking brake or just leave my foot on the brake. it doesnt seem to do it in anyother gear.. I am going to try the plug thing since that worked for someone and it doesnt do it anymore since then...