OK. So it's been over a week since replacing the fuel pump. noticeable improvement. It's got the power back. No problem there. First thing in the morning starts right up. But I have a minor issue now, when it's warm. I had an issue with it at idle. it was stalling out once in a while. Or trying to. Actually did stall once when I came off the freeway and let off the gas. and was coasting. Started right back up though. And when taking off, like sitting at a light, it would occassionally hesitate if I gave it the gas real quick. I replaced the iac valve with a used one. that seems better. No stalls, no hesitation. But still, it takes a few cranks to get it to start when it's warm. Nothing like it was when the fuel pump was bad. But noticeable. Could the iac still be an issue, since it's used? I think Possibly. Or could the TPS have a dead spot? I have a spare one of these too and am considering swapping it. But doubt this as the takeoff is smooth now.

 

well i dunno if it pertains to chevys, but when my dodge has a prob idleing its a clogged TB, the throttle blade sits slightly open to idle properly so when its clogged with carbon it idles like crap, may be worth checkin out

 

Actually my butterfly valve was crappy before. I've since cleaned it. I had a sticky throttle. Noticeable while we were up north in the winter. But it's clean now. but then again it's not a tb. What is happening is it'll start normal first thing in the morning. But when it's hot (which it has been lately, hot outside I mean, the truck isn't overheating) it has a hard time starting if it sits for a few minutes. I picked up the kids today and it wouldn't start at first. And it was cranking like it wasn't getting any spark. I'm going to check the coil tomorrow. It did overheat when the radiator was destroyed and I had to drive 2 miles down the road. I'm wondering if the coil is going bad or a sensor is maybe worn out.

 

Silly question, I know, but have you done a fuel pressure test paying particular attention to the leak down rate after you turn the key off? It is possible that there is some fuel leaking into the plenum that is causing the engine to partially flood.

 

Haven't done an actual pressure test. I know I probably should. But it seems to be more of a spark problem. I think I'll check that next week though. I'm going to test the easy stuff I can for now. I mean, I already replaced the fuel pressure regulator. And when it does fail to start it takes a bit to start. And occassionally it dies when I let it coast. Only once in a great while. 1ce this week. and once when I went to mash on it to take off from a red light it gave out. Didn't stall but major hesitation. I let off the pedal and got it back.

But since replacing the fuel pump it starts up smooth now. No probs. and it's got power again on the road. It was an issue (well the strainer) I'm wondering, could possibly the TPS have a dead spot? Gonna check on the pressure though. I don't have a guage that will plug into the port. That's my only holdoff right now.

 

It is possible that the TPS sensor has a dead spot. You can test it by either back probing the sensor output wire to the ECU/PCM. The output should be around 0.5V at idle and smoothly increase to around 4.5V at wide open throttle. if it drops out at any point in time, the TPS sensor is bad.