My 1991 Volvo 240 has an extremely rough idle if it even starts at all, but at highway speeds it cruises fine?

Question

I checked my OBD, socket #6 was1's, but socket #2 had a 3-2-2 and a 1-2-1 which I think both relate to an Air Mass Meter issue ($$), but will I have to take to a mechanic?

The exhaust smelled of gas and the spark plugs were covered with it when I checked off of a quick 10 second idle, but i don't understand how i could drive 200 highway miles between stall outs (in the matter of a night)? I've had trouble before with my timing belt slipping and i don't know if the problem could be that at high rpm's the timing matches up well enough to keep me going, but in the driveway only 2 out of 4 are firing?

Anyway, i would really appreciate any help anyone can give to me, and if you need any more information from me, please don't hesitate to ask. Thank you.

Answer 1

most likely you do indeed have a bad maf sensor.
however these codes can be erroneously entered by disconnecting the mass air flow sensor and starting the engine [ this forces the computer into limp home mode] if the car actually preforms better in limp mode it guarntees that the mass air flow sensor is faulty. NOTE replace the thermostat for the hot air damper [located in the air cleaner housing] whenever the mass air flow sensor is replaced.
if your car does not run better in limp mode clear the codes and test fuel pressure [with a known accurate gauge] spec is 35 psi @ idle with vacume applied to regulator 40psi with vac line disconnected. and under no circumstances should fuel come out of the vacume port on the regulator [be careful around open fuel lines no smoking or unshielded lamps]
there are several other conditions that can cause your symptoms but try these first

Answer 2

Don't forget to de-sludge your engine and shampoo the engine compartment.. A clean engine is a happy engine. Always watch for leaking oil seals around the timing belt, and fix them as necessary. Check for proper functioning of your idle speed control valve, and de-sludge it. Remove and clean all hoses involved in crankcase ventilation (PCV) to prevent early sludge formation. If you can smell gas in your exhaust, be sure to solve abnormalities in F.I. system because unburned fuel will thin out your oil and cause premature bearing failure. When you have resolved these issues, use synthetic oil to prevent future troubles. Good Luck!!!

Answer 3

clean the intake, take apart the intake clean everything and check the accordion shaped plastic pipe for cracks. use electronic cleaner on the air mass meter, get a new throttle assembly gasket, remove the three nuts holding the throttle assembly to the intake manifold, clean thoroughly with carb cleaner. remove the flame trap and clean this out or replace as necessary. drive it faster! check out turbobricks

Answer 4

pull the vacuum line off the fuel pressure regulator on the fuel rail, it is probally loaded with fuel, if it is replace the regulator, and yes of those codes are related to the mass air flow sensor:
3-2-2 Mass air flow (MAF) sensor burn-off signal absent or faulty
1-2-1 Mass air flow (MAF) sensor signal absent or faulty

REPLACE THE MAF!

Answer 5

I had an identical concern with my ninety 3 lumina with the three.a million. they're prevalent for having defective coils. a number of of of the cylinders isn't getting sufficient spark to burn the gasoline/air effectively. The "omit" interior the engine isn't noticable above idle yet, such as you pronounced, as quickly as the RPMs drop because it warms up the idle gets tough and uneven. I had an identical indicators.

Answer 6

Vacuum leak!