96 chevy 1500 pickup 2wd with 305
I am having trouble with my truck when it is in a low idle speed in 5th gear. runs fine until you slightly give it gas in 5th gear, say around 50 or 60 mph. engine rpm rise immediately when hitting the gas pedal, then a split second later will lower and jump around (lower than it should be). It is kind of a sputter but is more precise, like driving over a rumble strip. I had some codes popping up. I replaced 2 o2 sensors, and an egr valve. codes went off, but this problem is not fixed. It tends to be more noticable when there is a load on the engine, like when i am pulling a trailer. The rumble will go away and rpm will rise as soon as i give it plenty of gas (about 2500 rpm). I have also checked the IACV. It had a funny clicking noise coming from it when warmed up, engine off, and key on. Not sure if this part is bad, because it seems to operate fine when parked and in idle, load or no load. Ever heard of this?