1994 n/a Volvo 854

I just don't understand what is going on.

Beginning winter I was having a no start problem. So I went through steps and ended up replacing/cleaning parts until I got it started. Then I started getting this problem where the car just doesn't really want to go at low RPM's. The problem was such that I could still get around semi-reliably and even drove for an overnighter some 200 miles away. That was about a month ago. Since then the problem has worsened to an extreme. I have been replacing parts all along, trying to figure this mess out, but nothing seems to work. Some things make the problem disappear for a day and then, like a virus, it comes back even stronger than before. Just the other day it got so bad I had to park it, and after one trip to the bank yesterday, I just want to fill the bitch with dynamite. It wont go anywhere. I had the transmission replaced about a year ago and I had the same sort of problem just after. It goes like this now: as I give pressure to the accelerator, nomatter how much, the car simply shudders. The RPM's rise as intermittently as the car shudders, so there's no miscommunication there. Once I hit about 10 MPH the shudder releases a little bit - less often, longer duration per no-power. By this point I'm usually flooring it, and it will kick in and power through the rest of the gear most of the time. For months now I've smelled something like burnt sulfur or "rotten eggs" when I get out after driving any more than 5 minutes, and sometimes even while I'm driving. When I replaced the throttle switch last week, I erased all the codes, and there were none but the 1-2-2 when I checked today... which, when I'm driving more than 45 mph and pop the hood and put the car on auto pilot while I climb out and check to see if the 1-2-2 has gone away, is very helpful. So I'm happy for that.

The replacement list goes like this:

Fuel Filter
Fuel Pump Relay
Spark Plugs
Distributor Cap/Rotor
Spark Plug Wires
CMP Sensor
RPM Sensor
Fuel Pressure Regulator
Throttle Switch

I just filled the tank when the REALLY drastic shudders started happening and added some "fuel injector cleaner" just prior - at almost empty as per the instructions. I also ordered some stuff that claims to clean the gunk inside the Cat, but it hasn't yet arrived.

Please, can somebody please help me. I thought i was at the end of my wire before, but now....

Thank you all very much. Now I know where to look. I suspected the temp sensors before when I was driving to class, and when I would get onto a bridge the car would act a little funnier (concrete temp on bridge different than other road). This could be mere speculation. Also, I think the cat is getting fried and could be causing the severity. Fuel pump is someting I will look into as well, but to me it seems more of a sensor problem at this point. As you all know, I've already spent much on preventative maintenance/guesswork. I can't explain enough how much I appreciate the few minutes you all took to read and respond with very thoughtful suggestions.

The rotten eggs smell is the catalytic converter. If it is blocked, you will definitely have acceleration problems. Have the catalytic converter checked, or tap on it under the vehicle and listen for broken ceramic particles inside.
brad

1-2-2 is air intake temp sensor, which is, I believe, either the EGR system temp sensor, or the ambient temp sensor. The EGR system makes more sense in relation to your problem, since the ambient temp sensor is for electronic climate control. As I'm sure you know, sulphur smell indicates a running too lean problem. If you could get somebody to stand behind the car while you do a brake stand (accelerate hard with your foot on the pedal)to verify if exhaust pressure increases with acceleration or leaves on acceleration this would help rule out a clogged exhaust. Not just the cat gets clogged, baffles fall apart in the mufflers as well. However, I'm leaning towards low fuel pressure, i.e. fuel pump. If the car will idle beautifully...forever...all day long in fact...but falls on it ass on accell...it's usually the pump.

well you certainly have spent a lot of time and money on this car, the 1-2-2 code is for the IAT sensor signal missing which can absolutely cause a problem such as you described. IAT on this car is screwed in to the t-stat housing. If you haven't already I would suggest a new thermostat at the same time. good luck!!!

Sounds like a possible plugged CAT.....

Today when I was driving up and down the block, twice I heard a small "pop" - kind of gutteral and quiet. Heard the same at idle when pulling the throttle from engine compartment.

Sounds like a blocked cat. Cat. convertors usually get blocked or otherwise damaged from a bad exhaust, such as engine running too rich or lean. Be sure to find out what messed up the cat if you need to replace it. Had the same problem on a '94 944 I used to have. The cause was a bad O2 sensor, which later on overheated the catalytic convertor.
--
'94 854 N/A.

Here's an update! I have had the car idling in the drive for about an hour and then drove it up the street and back. The problem is near gone! I know this is only temporary, but I'm sure this will help narrow it down for you guys. I don't know exactly what it means. At idle I feel the exhaust coming from tail to be normal, hot, and there is no smell. I don't know how to check the timing belt without part removal that I may not be skilled for. I can do simple tasks, but the more complicated ones I may need hands on help with.

Have you no codes? No check engine light? Sitting at idle, with reduced air flow over the engine, there is something that is getting hotter than normal, or is not being pushed around by air like normal. Of course the mixture is gonna go lean, rich, lean, rich, lean, rich, which means the 02 sensor may have burned off. Hmmm...check the terminal connections on the battery. You will see where a great number of wires come together, is this loose? Getting bumped and swayed in normal driving? This also powers the main relay, directly under the cowl in front of the fan. If you stand in front of the car, lean your head down, and peer back at yourself you will see a number of components attached under the cowl. One of them is a grey relay, your main relay, if the connector is loose, or it has fallen from it's home, this could also be your problem.