87 740GLE - Sounds like a fuel pressure regulator?
 

My car has been running well for a solid 6 months. I cleaned out the throttle body and cleaned out the residue inside the hose. Immediately, it began to run very rough and vibrate.
I considered it to be an exhaust leak, so I tapped it thoroughly with a rubber mallet. The area around the cat sounds like it has something in it. (Maybe time for a new one?)
The vibration and roughness produces poor power and I'm pretty sure I'm running a little rich. The car idles fine at about 750rpms. BUT when I accelerate to about 40-50mph, it goes away...

Could it be a hall sensor? Electric Coolant Temp sensors?
Any help/ suggestions would be appreciated.

Thanks, I need to get this brick running like a champ again!

Well, the cat may be bad, inside separating... Vibration and roughness are engine misfire, find the causes of that... The FPR is a tricky bugger, actually can cause a lot of problems in that car. Check the Hall for damage or oil contamination. Temp sensor not likely suspect but should be eliminated just in case.

Is there anything I should know about the FPR? Average price about $60-70? Is it better to buy used, or new?

a fuel pressure gauge hooked up and a reading different then spec. sounds more like a fpr to me. esp. if pumps and filter has been done.

Just bought a new filter. We'll see how this goes... How often should one change the fuel filter. I've heard anything from 60k to 10k. Also, should I have bought a spare fuel line, I hope I don't kink the line........

Well, when my car is running fine, I do work and then it runs like crap...I tend to first look at the work I just did. You worked on the TB and then cleaned "the hose". I'd check vac hoses in the vicinity, the TPS and the cleaned hose first. It's possible there is a hose misinstalled or torn, the TPS isn't plugged in or mis-set or possible the IAC is unplugged. Of course, it could be anything unrelated to your work. That's just where I start.

Tested the FPR. It wasn't clogged. My Dad and I changed the fuel filter. Changed the washers, and didn't bend or kink the fuel line. The car has returned to itself as far as acceleration, however it's still making a whirring noise in at low speed and has a bouncy idle. The engine bay became quieter from the fuel filter change, but now I notice
Now, I did mention I cleaned the throttle body earlier. I believe I used generic "carb/intake cleaner". Was that the wrong choice? I think I took off a teflon coating on the inside. Dun Dun Dun.
Is there any way I could remove it and properly clean it, maybe even put another coating of teflon? I really don't want to buy a TB!
The vibration could be the driveline, I'm not sure. I have the ZF4hp22 though. Supposedly it's not the best tranny.

In conclusion, the fuel filter needed to be changed and improved the acceleration, but I can still sense hesitation and rough idle.
Thanks again guys

@Swiftjustice- I thoroughly checked hoses and vacuum lines. Everything is secure and not leaking. The wires are mostly falling apart (nightmare) but I've heard that's common thing. The hall sensor was examined when I changed the distributor cap and rotor, and it was clean and operational.
The engine almost seems like it's losing pressure somewhere. The head gasket is clean, but I've never checked the header gaskets though.

I feel like I'm chasing gremlins every month in this car.:mad: Oh yes, mad smiley.

Meh...think of it as a journey towards getting back to stage zero. It's a chore re-doing things that have been ignored for 20+ years. Regular carb leaner is best. The only way to truly clean the throttle body is to remove it from the intake. Three 100 mm bolts and a couple hoses, unsnap the throttle linkage. Best to have a new TB gasket on hand when doing this; doubtful the existing one will survive. You will most likely find the back side of the throttle blade is still filthy...the crank case ventilation assures a nasty tb. I've seen them so dirty they would not close. If they don't close, the TPS won't know to include the IAC in the circuit. If I were to bet...I'd say you have nothing worse than a vacuum leak somewhere. I don't advocate arbitrarily throwing parts at a problem, but there are a few things I replace out of hand shortly after acquiring a "new to me" Volvo. One is every single vac hose under the hood except the hard lines going to the charcoal canister; small vac lines, brake booster line, iac hoses. The time involved in locating minute vac leaks is time I'd rather spend otherwise. But...that's just my opinion.

I have mixed feelings and responses about carb cleaner on fuel injected TB's. Hear some say it's okay, some say you better use cleaner for fuel injected cars. Now I have cleaned the TB (without removal) and hose between the TB and MAF before with carb cleaner. When I attempted to start it, I failed several times, eventually having to take the plugs out and clean them as they were soaked.
My thinking is, when you clean up all that unburnt fuel in the TB and hoses, you mess up the balance of the engine because it is so used to all that crap in there, all that crap and fumes that it is expecting to burn when you start the car. Now that you take all that out, the car runs lean and eventually adjusts with time. I would try disconnecting the battery next time and see if that settles things out right after a cleaning.
That's my two cents, as crazy as it may seem to some who know better, but hey, that's why this is a forum. :D

Sounds good gentlemen. I'm going to check out the IAC and clean the TB tomorrow. Random question: What is the proper idle rpms for my b230f?

I heard 900rpms is good, but it might be a bit much for the trans. torque converter. The transmission is a bit clunky as of lately...

I love the Volvo lifestyle and I've really been trying to get this car going. I'd love for it to last up to 300-500k. Any help is definitely appreciated, thanks again people.