Need help!!!! C4
Thread Starter
6th Gear
Joined: Aug 2023
Posts: 6
Likes: 1
Need help!!!! C4
I have an 88. Car runs pretty decent around town, but as soon as I get on the thing on the highway (usually when it kicks down) the car will make this noise until I let off the gas followed by what I can only describe as a limp mode(loss of power) and a check engine light. I can fix it by turning the car off and on again. I don’t know if it’s only when the car is hot, full or low tank of gas, or after a turn.
I’ve pulled the codes and the only one is a code 43 (not sure if a bad knock sensor has the same symptoms)
I’ve also recently replaced the spark plug wires
Can’t figure it out, any advice will help
I’ve pulled the codes and the only one is a code 43 (not sure if a bad knock sensor has the same symptoms)
I’ve also recently replaced the spark plug wires
Can’t figure it out, any advice will help
Drifting
Joined: Nov 2018
Posts: 1,766
Likes: 648
From: USA
Did you have this issue before you changed plugs/wires? Is the noise detonation/pinging? How does it idle? For starters I would verify proper firing order to all plugs (18436572, clockwise rotation), then I would run the engine in a dark garage and watch every spark plug for arcing (perhaps one got cracked when installing or a spark plug boot has a puncture/burn through), verify timing is set correctly. Are the cap and rotor new, how do they look? How about fuel filter age/mileage and I would verify proper fuel pressure. Gas...age, octane? From the limited description, I would guess detonation, investigate the ignition system/timing, I highly suggest you figure it out before you continue to flog the engine or you can add pistons and rebuilding your engine to the list! Give us some more details, good luck, you should figure this out relatively easy👍
Thread Starter
6th Gear
Joined: Aug 2023
Posts: 6
Likes: 1
Did you have this issue before you changed plugs/wires? Is the noise detonation/pinging? How does it idle? For starters I would verify proper firing order to all plugs (18436572, clockwise rotation), then I would run the engine in a dark garage and watch every spark plug for arcing (perhaps one got cracked when installing or a spark plug boot has a puncture/burn through), verify timing is set correctly. Are the cap and rotor new, how do they look? How about fuel filter age/mileage and I would verify proper fuel pressure. Gas...age, octane? From the limited description, I would guess detonation, investigate the ignition system/timing, I highly suggest you figure it out before you continue to flog the engine or you can add pistons and rebuilding your engine to the list! Give us some more details, good luck, you should figure this out relatively easy👍
Thread Starter
6th Gear
Joined: Aug 2023
Posts: 6
Likes: 1
I had the issue before but it has slowly gotten more frequent over time. The sound is hard to explain imagine the rpm’s getting higher and higher and then all of a sudden it cuts almost like it’s running with no fuel. I made sure to double check the firing order and it is all correct. My first thought was ignition, so I have checked all of the wires. Cap and rotor are about a year and a half old. car idles fine I just replaced the iac and egr (with delco parts). It could potentially be the fuel filter I had it replaced not too long ago but who knows. I feel like it’s fuel related but I don’t have much experience on cars, I’ll check for any arcing once it gets dark. Thanks
Thread Starter
6th Gear
Joined: Aug 2023
Posts: 6
Likes: 1
I don’t know what happened but I’m not having the issue anymore. I fixed an exhaust leak on my header, that could’ve been steering off the knock sensor. I swear this car makes no sense.
