On the advice of this forum, I checked, cleaned and tested the EGR valve on my 3.8l v-6-equipped '89 Ols 88 to help with a stumble on accelleration with 3 codes indicating EGR flow check. The EGR valve appears to be working fine, so I began looking at the exhaust gas O2 sensor. Since I don't have a multi-meter that will read to .100 vdc, and the price of the sensor was reasonable enough, I replaced the sensor and the spark plugs at the same time. I used Bosch Super spark plugs and a Bosch O2 sensor. Now, at other times in this forum, I have read that GM vehicles PREFER AC/Delco spark plugs. Is this also true of the O2 sensor? And, after disconnecting the battery to clear stored codes, will the ECU need time to "learn" the new sensor? The reason I ask is that the car stumbled a couple of times for my wife on a short trip to the grocery store. I was able to make the car stumble when I drove it after she returned home, but continuing to try to make it do it again under different rates of acceleration, the problem seemed to get less severe. What's up with that? I would appreciate any ideas from anyone who's got one. Thanks in advance - Chris

Hi Guys! I was starting my 1990 ranger with a 4.0 V6 (1st time in the morn) when I heard a pop under the hood. Looked under the hood and saw a vacumn line (BLOWN?) off of the fitting that delivers vacumn to the brakes. FIVE vac lines on that fitting. I have a rough idle and suspect an intake manifold vac leak. What do you think? And; where do all them vac lines go? Tony ........