Lil Mama

Hello all,
I haven't been on here lately so I am a little embarrassed about dropping in for help, but if you could be so kind as to help us out we would be grateful. Anyway, our 87 was always an example of a flawless running 928( if such a thing exists!) . But recently it has been a little down on power and having some fluctuations in idle, like it is taking gulps of air , but just a little. We installed a new air fiter and a maf from John Speake also new spark plugs. The gulping fluctuations are still there, along with the lower power. We pulled the plugs to change them and we were surprised to see all of them fouled and gas-soaked. We pull one every so often and usually they are a nice tan color. We established the low power by using a G-TECH SS PRO. The car will usually pull 0-60 in 5.3-5.6 depending on the shift , but the best it can do now is a 6.5. on the same stretch of road I always measure on. What do you think this could be? Btw, I am posting on my wife's acct. mine is still and always will be active, I just could'nt figure how to log on to mine via Laura's computer!
Thanks to all.
Kevin

Randy V

At the upper right of any forum page - click on the 'Log Out' link.

Then, log back in with your ID.

John Speake

O2 loop ?

Lil Mama

Thanks , Randy. Mr. Speake, The new maf you sent me works perfectly, and I am sure improved our car.It is a comfort to know that it has been replaced! How to I determine if it is the 02 loop? Also is this the most probable conclusion?
Thankyou,
Kevin

sublimate

You can unplug your O2 sensor and if it doesn't get worse then that is probably the problem.

Lil Mama

How might one go about this procedure? Don't want to sound dumb, but i am not familiar with this car's 02 sensor.
kevin

jserio

I have an 87 also. I believe the O2 is connected by the fuse panel. I think I saw it there when I was working in there. Take a pic of your fuse panel area and maybe someone can point it out to you.

Jim M.

The O2 senor connector should be laying on the floor just in front of your fuse/relay panel in the RH footwell. It's a round 3-wire connector about 3/4" in diameter. It just pulls apart and is murphy proof so it can't be put back wrong. One end of the wire goes back behind the fuse panel and the other goes under the carpet to a grommet in the tunnel where it continues to the exhaust pipe.

Jim Mayzurk
93 GTS 5-spd

Lil Mama

Thanks , I'll go out to the garage and give it a go. I'll update with results.
Kevin

Bill Ball

In my 89, the O2 cable and connector were hidden behind the lower board that is bolted to the fuse panel. Undo the 10MM nuts that hold that on if you don't see the cable right away. The cable is separate from all the other crap and can be traced toward the center hump where it passes through a grommet to the underside of the car above the cats.

Lil Mama

Thanks for the tip Bill. I finally found it there! The car really is acting up with the 02 sensor unplugged. Anything else it could be?
Kevin

Bill Ball

Well, you say the plugs are fouled and gas soaked. All of them? The MAF is new. The idle is fluctuating a bit.

It's not classic, but if you can find somebody local with an LH brain, I'd swap them.

Beyond that, I'm not too sharp in this area. Others may be able to say whether a bad temp sensor would cause this. You appear to be overly rich from the description. Does the car run better when cold then get worse as it warms up?

You put in new plugs. How about the caps, rotors, coils and plug wires?

Lil Mama

Hi Bill,
Nope. Have'nt done those yet, as I believe the p.o. did. It all looks new and no fireworks in the dark. This thing has always been a top runner since I've owned it, then one day it just did'nt idle right or feel the same. The engine has a little more vibration when you throttle it from the engine bay and it sounds a little choppy, like when an engine runs lean. Never did that, used to be smoooooth. I will look for a brain to see if that works. Could it be the temp2?
Thanks for helping us, bro, we owe you one
Kevin

the flyin' scotsman

If the plugs are rich/wet then the issue is with the fuel system..........dumping in too much fuel. Considering the car ran worse with the O2 sensor unplugged, and the MAF is new then you should move onto to possible stuck injectors and the LH brain. Check the injectors as per the WSM and swap out the LH with a known good unit.

One quick reset of the brain might something to try...........disconnect the battery, reconnect after a few mins and see if there's a diff...........if not see above.

Lil Mama

Would the ezk unit be a possible culprit?
Kevin