Misfire started after taking off cold air intake and clean the filter?

TWOCANANN

MEMBER
1996 CHEVROLET SUBURBAN
5.7L
V8
4WD
AUTOMATIC
230,000 MILES

Started after we decided to take off cold air intake and clean the filter. Didn't run right afterwards. Started misfiring. So, we changed the plugs wires cap and rotor. Still misfired and backfired. A plug wire was wrong, so we fixed it. Still misfiring changed cam sensor and a used crankshaft sensor. Still misfires. Last time I drove it, there was no light on, and it ran great until it warmed up. The light came on started misfiring and backfiring again and gradually kept getting worse and worse until it would barely go down the road. Let it cool off a couple hours and drove it home. Then after it warmed up again the same thing happened. Light is on again on my way to borrow a acanner. Will guve an update after I get the code. Any insight would be greatly appreciated.

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

If you removed the air intake, you may have damaged the mass air flow sensor. Since this started after you removed the cold air intake, that would be my first suspect unless there is a leak because something isn't fully mounted. Any air that gets into the engine that is unmetered (after the MAF) will cause problems.

Since you have an aftermarket cold air intake, I'm not certain how it is set up. However, there has to be a MAF in there at some point. (Pic 1 below shows the OEM type) If you bumped it or got any solvents or cleaners on it, chances are it is damaged.

Check that first, make sure the wiring to it is properly connected and not damaged. Also, make sure the inlet is fully seated not allowing unmetered air to get into the engine. Also, if you disconnect it, the engine may run better if in fact it is damaged.

Let me know what you find.

Joe

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