I have been having trouble with the neferious bucking at low speed, steady throttle problem on my 87 GT. I have replaced about everything in the ignition system. I have noticed that my No 1 plug is slightly carbonned up. Dry black powder, all others are clean. I think it is related and I think it is a bad injector. How do you check them? Any other ideas? Thanks for any help here.

------------------

Dwayne Mohr
84 SC Red
87 GT 5sp Silver
(Formerly FieroSoul, member since 2001)

TTT

the carbon can also be from a leaking valve stem seal. You need special equipment to check the injectors. The best way is to take them out, and get them cleaned & flow checked. But, that leaves the car down for about a week (shipping mostly), but its only $70. The next thing is where the injector harness is plugged into a box that measures the fuel pressure, and fires each injector for a set amount of time, and measures the differences in the pressure to look for uneven flow, clogged, and for leakers.

Black carbon build ups on plugs are often from burning oil. That cylinder might be blowing oil past the rings or valve seals. Do a compression check to see if that cylinder is lower than the rest.

The carbon is pretty light and not really oily. I can still check the compression but I am not sure that's it.

I forget how easy it is to post pictures sometimes. Here it is.

Bump

Will a bad pattern make a plug carbon up?

TGraves

I don't know TG. I think it may be dumping too much fuel. Doesn't this carbon look like it is running rich?