Alright, I've searched this site high and low for solutions to this problem, and have found plenty of info, but nothing I've tried has fixed the problem so far, so I'm asking if anyone else has ideas or suggestions... so bugger off search ****'s, I've done my homework.

Now, to the point. I have a 91 GS with a B18A1. Mostly stock, except for the exhaust. It's running very rich (black soot all over the white rear bumper) and has an audible misfire at idle and partial throttle. When I let off the gas it will almost die from time to time, the RPM's drop so low that the whole car will shake, and then just die if I don't stab the gas a bit to keep the revs up. The car came to me like this from the previous owner.

I've been driving it back and forth to work like this for a while, and last night driving home the check engine light came on for the first time. I pulled over and pulled up the carpet on the passenger side and checked the code... 4 long blinks, 3 short. Code 43 is Fuel Supply System.

Here the list of what I've done so far in troubleshooting this problem:

Thoroughly cleaned IAC valve with carb and choke cleaner.
Checked/cleaned the fast idle valve (the plastic piece was snug in there, not loose)
Sprayed all the vacuum lines/fittings with carb and choke cleaner hoping to find a vacuum leak (none that I can find)
Checked timing
Replaced O2 sensor
Changed plugs, wires, rotor, cap
Did compression test
Replaced MAP sensor

The car acts almost identical to my old Civic when I had a vacuum leak, down to the code and the rich exhaust smell and wierd idle (forgot the little O-ring on the MAP sensor on that one, took me a while to figure out), so that's what I'm leaning towards, but if it is leaking, I sure as hell can't find it.

I took the intake hose off today before I checked the FITV, and put my thumb over the lower hole inside the throttle body... the car was completely warm, but there was vacuum there, which was what made me decide to take the FITV off and check it... I thought once the car was warm the FITV was out of the loop, or am I wrong there? If I plug the upper hole, the car dies like it should (no air through the IAC valve).

So what else am I missing here? I've noticed a lot of people with problems like this and no definite answers... I think I've covered most of the suggestions I read in the threads I searched, and now I'm stumped. Combining this problem with the overheat problem I've been having with this car and I'm about ready to drive it off a cliff.

Thanks in advance if you've got an comments or suggestions. I'd really appreciate it.

 

Bump... I know it's a long post... but I really need help with this...

Cliff notes: car runs rich, throws CEL 43, misfires. I've tried everything I can think of to fix it (see list above). What else could it be?

 

did u reset the ecu?? also are ur plugs gapped right?

 

Yes, I've reset the ECU multiple times.. pretty much every time I made a change... took the negative terminal off the battery and let it sit for 10 minutes then put it back on and started the car up. Correct procedure?

Plugs brand new NGK's gapped at a hair less than 0.040 (probably like 0.039).

 

did you change the fuel filter.What was your compression results.How many miles.

 

Fuel filters are culprits of clogging and not allowing sufficient flow. Also maybe check your fuel pump. It may be trying to stall out cuz its not getting enough fuel. I would start with the filter then check the pump.

 

I've already replaced the fuel filter, forgot to mention that in the previous post.

Anyway, I really don't think it's a fuel starvation issue, the car runs very rich, not lean. Black soot out the tail pipe, etc. It's not stalling because it's starved for fuel, it's stalling because it's getting too much fuel. I'm going to pull the plugs again today and check them, but I'll bet they'll be black.

Compression results were 175, 170, 175, 175. Plenty of compression.

 

Bump because it's getting worse... I can't start it and let it idle and warm up now, it requires constant throttle to get it warmed up, but last night once it warmed up it idled at 1200-1500 out of the blue and didn't stall at stops. This is getting ridiculous...

Yesterday I made a meak attempt at troubleshooting some more, but I'm not sure where to go from here... I pulled the PCV valve hose off the IM and blocked it's port off, same thing. I did another round of the "spray the hoses" game, this time with starting fluid to see if the revs jumped at all. No luck anywhere on any of the vacuum lines or where the IM meets the head. Everything is screaming vacuum leak, but I cannot find it for the life of me.

Could this be the Ignition Control Module (ICM) in the distributor? The parts store wants 90 bucks for one, so I'm not going to plunk down the cash just on a hunch unless someone can tell me similar experience. Maybe I'll see if I can find someone that will lend me theirs for a couple hours.

Stuck/leaky fuel injector? I dunno, grasping at straws here. All the plugs look good, little black, but dry not wet.

What the heck's going on here?