92 running real rough

hey ya'all
I've read some posts and most of you seem pretty good at what you're doing so I figure I'll ask.

I have a 92 grand am not sure what size engine (I'll find out tonight though) I know it's a 4cyl DOHC (but not a quad)
was running great until about a week ago
started almost unoticeable, when driving gas pedal seemed to pulse ever so slightly
stalled out on me 2 days ago at a light, I thought it was me forgetting the whole clutch/gas balancing act thing but I guess not
next day it stalled as I was turning into a parking lot, no explanation for this, ran fine after I came out of the store and started it back up
today ran fine this morning, now runs like crap, like the poor car was castrated

current symptoms
loss of power,
still accelerates just not nearly as fast as it used to

smell,
smells like exhaust inside the car and outside, much worse than ever before

engine shakes,
not real bad but there is some shake, rattle and roll going on

coolant is cold to the touch, manifold/header, whatever it is, is very hot to the touch but I can open up the coolant cap and touch the antifreeze, it's lukewarm at best

sound,
sounds almost like a pinhole exhaust leak, or like I put a new high performace exhaust on (kinda like an old muscle car almost)

what has been replaced recently
spark plugs/wires (within 6 months)
O2 sensor (same time as plugs/wires)
there may be more but I just got the car so I'll have to ask the previous owner (he's a good buddy of mine, and I'll be talking to him tonight)


any help would be extremely appreciated,

Cool coolant, hot exhaust. Sounds like a bad cat. converter or a restriction in the muffler(s) or in the resonator. By the way, if you have a dohc 4cylinder in a 92, then its a quad. Check your temp gauge, it should be around 180-200 driving in traffic. If its running hotter than that, check your water pump and thermostat, both are located on the bottom back of the motor. The water pump is a real bear to get to, the exhaust manifold has to come off. Also, check the donut gasket on the back of the motor where the exhaust manifold meets the exhaust pipe. If the cat is clogged, it might be blowing exhaust back through the donut, which would explain the strong exhaust smell in the car. Good luck.

thanks for your response.

the temp guage used to go to the 1/4 hash mark when I first got the car about 6 weeks or so ago, now it just barely comes up from the off position (maybe 1/8 inch from it's rest position)

the donut gasket at the manifold looks like it's seen better days but there's nothing visible coming from it (no exhaust, nor air if I put my hand near it)

clogged converter was one of my ideas also, along with a faulty throttle position sensor or bad plugs/wires, but my buddy who is something of a mechanic ruled out the TPS and plugs/wires, I don't know I'm much more of a computer fixer upper than a mechanic, (I can turn a wrench with the best of em though)

one more question
when the car is running and I have the radiator cap off, should I see motion in the coolant? I would think so but I don't, also don't feel any motion when I squeeze the hoses like I think I should. But if I'm overheating why does the car still act weird after it's cooled down/cold to the touch

also
when running and the motor is hot the exhaust coming from the tailpipe is cold, what could cause this?

some new information
no check engine light but jumped the 2 pins on the OBD1 panel
got the code 35 which tells me nothing

Idle speed was over 175 RPM outside the desired engine speed commanded by the ECM for at least 5 seconds.

so maybe idle speed sensor or idle air control sensor???
talked to someone else so also said IAC so unplugged it and it ran excellent for a few seconds then started to surge, plugged the IAC back in and it was the same as before.

Code #35 for your car is the idle air control valve or circuit. The iac valve is located on the throttle body, goes for around $75 at autozone. Your low temperature is caused by your thermostat sticking open, on the 93's its on the drivers side of the cylinder head, just follow the upper radiator hose back to the motor, its under the housing coming off the head. on 94 and later models, its on the back of the motor under the exhaust manifold, and they suck to change. I did mine on my 95 in December, and it was COLD that day... good luck With the thermostat sticking open, you will eventually see motion in the tank, its just going to take a while. My 95 takes around 35-40 minutes at idle for the cooling fan to turn on the first time, and with the thermostat sticking open, it will take longer. you can speed up the process a little, run the ac if you have it until it reaches normal temperature, around the first mark on the gauge, then turn the ac off so it turns off the fan, and keep the car running. as it heats up you will see some motion in the tank, if you don't until the fan kicks on and it starts throwing up out of the tank, look to a blockage somewhere.

thanks a lot man
that makes 3 votes for IAC and they're $66 at my part store in stock, so tomorrow I'll be changing it.
thanks for your help.

tom

changed the IAC valve and still running rough.
did what the chilton said as far as grounding the thing and waiting 7 minutes etc... to reset the IAC

took it out on the highway to see if getting it up to speed would do anything, dumped about 1/4 of a tank (maybe a little more) in about 16 miles.

smells like gas in the oil, everywhere in the car etc...

what would cause the car to dump all this gas in such a short time?
any ideas would be greatly appreciated I don't have the money to be changing parts

Check your plugs. Sounds like you have a plug or 2 not firing right, this will cause gas to be dumped into the oil and into the exhaust. Also check the wiring going to the iac, check your manual see if it has any information on when it is supposed to get power and what the readings are. Also look for an external fuel leak. See if its dumping on the ground anywhere. Anyone else out there have more ideas?

it's dark now so I can't really do much

first thing tommorrow I'll check the plugs,
no fuel leak, externally anyway
what about 02 sensor? could I have ruined with the fuel being dumped into the engine?
or maybe a throttle position sensor
how about the spark plug module (coil pack)

o2 sensor would give you a check engine light and a code 13, 44,45, 55, or 61. 13 is either bad sensor or circuit, 44 is lean exhaust, 45 is rich exhaust, 55 is circuit or ecm, and 61 is faulty sensor signal (possible contaminated sensor). Check your manual on the way to test the throttle position sensor, they are pretty easy to do, and remember if you take it off to make marks on it before you take it off so you can reallign it without any problem. coils do burn out after time, its something fairly easy to check, the manual should have the information you need.

if my cat is glowind orange does that mean its definately clogged?
keep in mind the car has absolutely no power, barely gets out of it's own way

if my cat is glowind orange does that mean its definately clogged?
keep in mind the car has absolutely no power, barely gets out of it's own way

That'd be a big 10 - 4 there buddy!! :thumbsup:

Its definately clogged, and its probably burning gas. Be careful driving the car, it can catch on fire from the cat (had this happen with the ex wife's car). Find the problem with the cat first, probably running rich, correct it and change the cat all at the same time. If you replace the cat and wait to fix the problem you will nuke another cat.

had the cat cut off today and it was not clogged at all, checked the plugs and it's not firing on 1 and 4, what would make it not fire on these two cylinders?

There are 2 coils on the quad 4's, one coil fires #1 and #4, the other coil fires #2 & #3. To test it, use a mulitmeter, set it to 20k for resistance, measure the resistance between #1 and #4 outputs, should be 10k, if its more the coil is bad, replace it, they are around $30 each. The orange glow in the cat was the unburned fuel coming out of the motor burning in the cat, I've seen cats melt before.

it did turn out to be the ignition coil after all, replaced it and now I'm back running like a champ, better than ever in fact.
thanks skibum for all your help I probably wouldn't have fixed it without you

thanks again
tom

Not a problem. I've run into most of the problems that I have seen here since i have a high mileage car (236000 and counting...), and I'm more than willing to share the info on them...

My car was doing something similar to this one and couldnt figure out what it was. Good thing i found this post and only spent money on a new cat.
I got 2 new coils today just to be safe and it fixed my problem.

1992 Pontiac Grand Am SE QUAD4

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