I have a '98 K1500 with 201,000 miles, 5.7L vortec engine. My truck throws the P0304 code when I'm trying to accelerate up a hill, it only happens on fairly steep grade when I'm trying to get up to 55-60 mph. I've changed the TPS and MAP sensor. There's about 25,000 mi (4 yrs) on the spark plugs, wires, and distributor cap/rotor.

I'll post a couple pictures on the FOSEAL code reader freeze frame data. Any help is appreciated.

-Caleb

 

Here is the read out from my code reader:

Trouble code is P0304 - Cylinder 4 Misfire Detected
Freeze Data also lists P0300 - Random/Multiple Cylinder Misfire Detected
Throttle Position: 57.65%
MAF air flow rate: 75.26 grams/sec
Speed: 54 mph
Intake manifold absolute pressure (MAP): 0.92 atm
Long term fuel % trim - Bank 1: 8.59%
Engine RPM: 2264 rpm
Short term fuel % trim - Bank 1: -4.69%
Engine Coolant Temperature: 199.40 *F
Engine Load: 34.12%
Fuel System Status: 2) Closed loop: using O2 sensor for fuel mix
Long term fuel % trim - Bank 2: 7.81%
Short term fuel % trim - Bank 2: 1.56%

Thanks,
Caleb

 

 

fuel filter?