Ignition Wires

[fwappy]

My car is running a little stumbly, and after concluding there were no vaccuum leaks I began to look at the ignition system. My cap to plug wires read resistances around 5800 ohms, except for #1 that was 6200 ohms. The repair manual says they should be between 4500 and 5500.

Do they need to be replaced? I wouldn't think so. Cap and rotor are both new. As long as they are firing then all should be ok, right?

Also, would a bad fuel pressure regulator cause a loss in HP and stumbly idle? How would I check that?

[dark89e30]

Considering #1 is your shortest wire, it is definitely bad. And just because they are firing does NOT mean they are ok. There is a long explanation behind this but basically, you need to replace them. FPR... If it is not spiking the pressure with revs, you will have a huge loss of power, as I experienced a couple of months ago when I discovered that AEM doesn't use and sealing compound on their threads. It was a very small leak that resulted in a loss of 30hp or so. You will need to hook a pressure gauge and measure FP with and without vacuum (unplug the vacuum hose). You should see a jump or 7-8psi with the fuel pressure regulator exposed to atmospheric pressure compared to vacuum at idle. If you have access to a vacuum gauge, hook that up and and see if the FPR holds vacuum. There should be NO loss of vacuum.

[jlevie]

If the wires, rotor and distributor cap are original they need to be replaced, period. That may or may not help the idle. A rough idle can be due to; ignition problems, intake leak, aged O2 sensor, improper valve clearance, bad/sticky ICV, bad AFM, or fuel system problems. Fixing it is a matter of eliminating possibilities.