Frustrating
Thread Starter
1st Gear
Joined: Feb 2020
Posts: 1
Likes: 0
From: Dade city fl
Frustrating
Hey, I have an 87 C4..it has been running rough and backfiring through the intake. I have changed everything. The MAF and both relays, plugs and wires, the IAC,ICM, and the Computer is new. Removed and cleaned the injectors and checked them with an ohm meter. It’s driving me crazy..any help is appreciated..also changed the cap and rotor..
Advanced
Joined: Apr 2022
Posts: 67
Likes: 9
Would agree--more info needed
Conditions, idle, load, RPM band, etc
Is there valve train noise?
May want to look at valve train for flat cam on exhaust lobe
Possible intake valve "hanging open"
Understand, far down the list
But............been there, done that
Conditions, idle, load, RPM band, etc
Is there valve train noise?
May want to look at valve train for flat cam on exhaust lobe
Possible intake valve "hanging open"
Understand, far down the list
But............been there, done that
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Melting Slicks
Joined: Mar 2002
Posts: 2,874
Likes: 764
From: Sligo PA
Do what everyone else said and if that doesn't fix the issue I would ask what you did to "clean the injectors".
I had this same issue a while ago and found that a Fram fuel filter had deteriorated from the car sitting with gas in the fuel line for a year. When I went to start it the fuel pushed pieces of the glue that held the filter element together into the injectors. I removed each injector and used a pick to clean them. Then following a video I watched I rigged up a simple 12 volt pulsing circuit and a rubber hose with a can of carb cleaner. I blew the carb cleaner through the injectors both ways until it flowed well while pulsing the injector. This is really the only way to "clean" an injector without taking it apart.
I doubt this is your issue. You have some very solid advice from everyone else. But if all else fails you might want to look at the injectors.
I had this same issue a while ago and found that a Fram fuel filter had deteriorated from the car sitting with gas in the fuel line for a year. When I went to start it the fuel pushed pieces of the glue that held the filter element together into the injectors. I removed each injector and used a pick to clean them. Then following a video I watched I rigged up a simple 12 volt pulsing circuit and a rubber hose with a can of carb cleaner. I blew the carb cleaner through the injectors both ways until it flowed well while pulsing the injector. This is really the only way to "clean" an injector without taking it apart.
I doubt this is your issue. You have some very solid advice from everyone else. But if all else fails you might want to look at the injectors.
