Hi again, relatively new person here trying to figure out more car repairs on my own.

My 94 Volvo 850 Wagon Non-Turbo has had an odd quirk with idle for awhile, but now it's morphed into a full on problem. For some time, upon starting the car, the idle would surge from 1k to 2k and back for a few seconds before landing on a steady 1k. Shifting from park to drive would drop it from 500 rpms back to 1k. It seemed to have no effect at all on the actual driving of the car so I ignored it.

Now it's changed- whenever the car is stopped or in park, idling, the idle will slowly sputter below 1k, then surge above 1k, then sputter below 1k, and surge back up again. And the real problem: when it's doing this, and I go to hit the gas, I get no response- just a tiny sputter, maybe nothing from hitting the throttle. Then, usually, three seconds later, the throttle opens up and the car surges forward. The whole time I'm pumping the throttle trying to get it to go. I believe one time I smelled a strong gasoline smell, but I need to check more times to be sure.

Once the car is in gear and moving, all seems fine, except for a slight, barely perceptible lack of usual power. Once I hit another stop, it's back to sputtering, and then - about 50/50 - no immediate power when hitting the throttle.

It somehow hasn't died outright, ever. Is this the fuel pump, a sensor, or the idle? Thanks for your help everyone.

EDIT:

codes:

Bank 1 :

124 Mode selector faulty or short circuit to ground
213 Throttle position (TPS) signal too high

I've cleared these, they come back.

Bank 2:

1 1 1 CLEAR

Bank 3:

411 Left front wheel inlet valve, open/short
412 Left front wheel return valve, open/short
413 Right front wheel inlet valve, open/short
414 Right front wheel return valve, open/short

I can't clear these.

Bank 4: blank
bank 5: blank

bank 6:

314 Camshaft Position sensor (CMP) signal missing or faulty

I actually had the Camshaft Position Sensor replaced a few months ago. It was giving me all kinds of other problems. I think I forgot to clear this code from back then. I cleared it this time, I'll see if it comes back.

bank 7: blank

 

From the codes, your throttle position sensor may be bad. Otherwise, it sounds like it may be related to the MAF sensor or the idle air control valve. Try disconnecting the MAF sensor and see if there is a difference.
That 124 code seems to be related to the transmission. Not sure if that has anything to do with the idle issue. Maybe a bad PNP switch.
Also probably unrelated to your throttle issue, but those 41X codes probably have something to do with your ABS module. Do you have an ABS light on by any chance? You might have to have the ABS module rebuilt.

 

Based on those symptoms, my first guess would be a vacuum leak and/or dirty IAC valve. Do you have a vacuum gauge? Do you know how to find vac leaks?

Stage0?

Yeah, see if the CMP code comes back; you may have wiring issue if the part's good.

BTW: the pre-96 MY ABS don't have the solder issues like the '96 MY and later. Clear those codes as well and see if they come back.

Re-reading your post; you're saying the 124 and 213 codes are solid? Then sure, what dubya said. Bad or disconnected TPS could possibly cause those symptoms.. You've got some diagnosing to do..