Hey how is everone, I tried using the search feature but really didn't see a definite answer to the issue I have but did try a few things. I have a hesitation issue with my 87 IROC that has the LB9 engine. So far when you start the engine cold or hot it idles aroudn 1500-2000 RPM (I believe I need to reset the idle to 600rpm) but at idle it's not bad at all. When you hit the gas in park the engine seems to stumble on itself. I have checked the injectors but I got a reading of about 15.7ohms. I still need to check the fuel pressure. All the vacume lines are hooked up correctly, I believe the timing is set at 6 degrees and the fuel pump was replaced in 2006. I'm guessing maybe FPR? EGR? Also the O2 senor is getting a lean mixture code from the computer. If anyone can help me out with my issue it'd be greatly appreciated!

 

first check the spark plugs .. see if there white (lean) or black (rich) ..

if there white .. than the computer is right and theres something wrong with the fuel, probable the fuel pressure or something (do you have an adjustable regulator)

if there black .. try changing out the o2 sensor .. there $13 from summit .. dirt cheap, plus they'll help gas mileage if your old one is worn badly ..

also .. check simple stuff like the pcv valve (driver side valve cover near back) heard they can cause some stuff if there blocked ..

i'd go off of what the computer is telling you right now .. its saying your too lean .. and thats why you have a hesitation, the computer is trying to add more fuel and takes a while to do it ..

hope that helps a little ..

 

Thanks Adrian. I'll check all that when the weather clears up. Rainy and snowy right now so I can't really do any work on the car now but yeah I have brand new spark plugs ready and waiting to be put into the engine :P. I checked the PCV valve and it's not blocked which is good. I'll probably end up getting the O2 sensors, those are dirt cheap! I have a ford probe and the O2 sensors for that are like 80-100 bucks each, it's horrible. I have the stock regulator as well but I was hoping to get myself a AFPR but I'll checkout the plugs first. Thanks again!