mmm98

I checked the IAC again this morning and I had good resistance on it- are there any other checks I should to do make sure it's functioning properly? How about checking the fuel pressure regulator? I checked my Haynes Repair Manual and they had no suggestions for testing it, only replacing it, so any advice would be welcomed.

I have a 1994 Chevy C1500, 5.7L engine. My truck idled high and I finally got around to replacing the idle air control valve. This didn't fix the problem and it continued to idle high. I determined the issue to be a vacuum leak, so I replaced my vacuum hoses and checked connections. I tested by spraying carb cleaner and the engine still bogged down at this so I cleaned the throttle body and made a new gasket for the throttle body because that one was falling apart. After doing this, the truck began idling extremely low. It threw the EGR code, so I have since replaced the EGR valve and EGR solenoid. Neither of these fixed the problem. Next on the list is to replace the throttle body gasket along with the distributor cap and rotor. Additionally, my truck will also struggle to accelerate. The confusing part is this- there seems to be no rhyme or reason as to the low idle. Sometimes, the truck idles in park at 800-900 RPM and is able to adjust the idle to the load of the AC being turned on. Other times, it idles in park at what is most likely 300-400 RPM because it doesn't even register on the gauge. It does not seem to have any consistency as to if the engine is hot or cold- it just seems to be whenever it feels like it. This evening, while working on it, it started straight up once and idled great at 800 or so RPM and handled AC and headlight load. While the AC was running, we unplugged the wire that makes the AC compressor run- this dropped the RPM down to around 700 and it never recovered from that. The truck was turned off and started again. This time it idled around 700. Truck was turned off and started again- this time it idled around 500-600. The truck was turned off and now it had to be given gas to start and idled low, around 400-500. Any ideas to explain what is causing this? We are all going mad trying to troubleshoot this and figure it out. We've checked so many things and nothing seems to be causing the problem. Any help would be greatly appreciated.

I have a 1994 stepside Chevy C1500, 5.7 L V8 engine This past week, my truck has started acting up. Within the first 5-10 minutes of driving, after being at a complete stop at a light or a stop sign, when trying to accelerate, the truck engine along with the inside electrical system dies. Sometimes it’s a barely noticeable skip but sometimes it shuts off enough for the radio to completely turn off and back on again. As far as I can tell, the dash lights, AC control panel, and radio all turn off as well as the engine but for less than a second. This has happened pretty consistently for the past week, but it only happens once or twice within the first 10 or so minutes of driving which makes me think it has something to do with the truck warming up. For the first time today, the speedometer dipped by 20 mph for a second before jumping back up to normal and then a few seconds later, the truck revved up by about 1000 rpms before dropping back down after a second. I’m at a complete loss as to the issue. I’ve checked battery connections and alternator connections. Everything appears fine to me. Does anyone have any guesses? I know that I need to replace the idle air control valve which is on my list of things to do, but I don’t think that’s the issue because I can’t imagine how that would be affecting the electrical components.