Hello new to the forum. I just purchased a 1990 c1500 short bed 5.7l. I'm having issues that I can't figure out. Ok so when I dive my truck when it warms up it will start surging and bucking. I'll pull over and restart and will be good for a few minutes then start doing this again. I replaced fuel pump and filter. Replaced temp sensor and swapped out ICM. Any help appreciated thanks
Surging and bucking when warmed up
- Thread starter short1500
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
Welcome. Where are some pics?
Also I've did a tune up as well. New cap, Rotor, Plugs, Wires.
Pull the vac line off the egr valve. Mine was doing stuff like this. I chased the problem for a while and the solenoid was pulling vacuum when it wasn't supposed to. Other thing could be a vac leak somewhere.
Ok I'll give that a try. Thank you. Also forgot to mention that I haven't had any code pop up either.
Only 1 picture as of right now
Attachments
The leaking egr wasn't throwing a code on mine either. These trucks don't have much for diagnostics. It will throw an egr code if you leave the hose unplugged while driving.
New to these trucks. So when I plug it off after disconnecting and it is my problem what should I replace?
Depends on what's wrong.
If the solenoid is stuck open, so that the EGR gets vacuum when it shouldn't, you'd replace the solenoid.
If the EGR valve is stuck open, you'd replace the EGR valve. Some folks have mentioned that the EGR valve vacuum nipple needs to be restricted on some applications, but the replacement valve has a fully-open nipple.
If the vacuum hose is connected to the wrong port on the throttle body, you'd re-route the hose.
And in any event, you ought to look at the intake manifold passages to make sure they're not partially-plugged with carbon. This will require a new EGR valve gasket, and removal of the EGR valve itself.
But all of that assumes that the EGR system is the problem, and you have not confirmed that yet.
If the solenoid is stuck open, so that the EGR gets vacuum when it shouldn't, you'd replace the solenoid.
If the EGR valve is stuck open, you'd replace the EGR valve. Some folks have mentioned that the EGR valve vacuum nipple needs to be restricted on some applications, but the replacement valve has a fully-open nipple.
If the vacuum hose is connected to the wrong port on the throttle body, you'd re-route the hose.
And in any event, you ought to look at the intake manifold passages to make sure they're not partially-plugged with carbon. This will require a new EGR valve gasket, and removal of the EGR valve itself.
But all of that assumes that the EGR system is the problem, and you have not confirmed that yet.
Similar threads
