CamaroJoe

I did the "pull each wire off the distributor" trick and cylinders 2 and 5 did not register any rpm drop. There is no noticable smoke of any color coming from the exhaust at low idle and I'm not losing a significant amount of oil or water. I plan on running a compression test once I pick up a tester and there is spark but I'll probably buy new plugs just in case, but I'm just wondering whats everyone's experience on injectors failing? Basically, how likely is it that 2 injectors or the wiring to them have failed? The car has about 120k miles and is of course a 91 L98.

CamaroJoe

I ran compression with the engine cold and all cylinders were very close, between 190 and 200 PSI. I remembered that the misfire happened most prominantly at normal operating temperature so I let it idle for 10 minutes. Then after burning my hand a few times I let the engine cool for 20 minutes or so and ran compression again and got the same results for cylinder 5(didn't recheck 2).

While observing the injectors I noticed that 2 of them looked different than the other 6. They were a lighter green on top with a polished looking bottom side, while the others were a darker green on top with a grey bottom. These 2 anomalous injectors just so happend to coincide with the cylinders that were misfiring. I checked their resistance and got 14.3 ohms for cylinder 2 and 8.0 ohms for cylinder 5. I then checked the injectors for cylinders 1 3 and 4 and got 18.0, 17.6, and 18.0 ohms respectively. I didn't check the other injectors because I figure I found my problem. Obviously injector 2 is bad and injector 5 is really bad. The car runs pretty good when cold though. Would an injector problem like this be effected by heat this much?