Engine Performance problem
1989 Chevy Silverado V8 Four Wheel Drive Automatic 185000 miles
i recently got a truck when I got it it had open headers on it I started it and drove it home no problum the headers were rusted out so I put new headers on and ran strait pipes ever sience then the truck will start and run fine in park but as soon as you put it in gear and have a load on the moter it stumbles and stalles right out iv replaced the o2 sensor and check all vacume line for leaks and couldn find anything what do you think it is?
Check the fuel pressure, throttle position, mass airflow, manifold absolute pressure sensors.
April, 4, 2009 AT 6:50 PM
Ive checked the map, maf, and erg valve and it still does it when you first start it up you can hear a loud air sound but cant find the leak could it be the tbi gasket
April, 5, 2009 AT 4:56 PM
Engine stumbles and hesitates: Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)
Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include: Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires
April, 5, 2009 AT 8:03 PM
Ok so when the truck is in park it it runs fine perfect no misfire nothing you can rev the motor in park and tell that it is runinig perfect you can see the gas that is comming out of the fuel injector flow faster when you rev the moter so I dont think it is fuel pump or pressur problums iv drained my gas tank and put fresh gas in it new fuel filter I chance the iac valve iv tested all wires and got all proper voltage to map sensor. Emc sencor. Tbi sensor.O2sensor. And egr silinoid and checked the egr valve changed all vacum lines cleaned injectors. But still when you put the truck in gear it will idil fine but as soon as you step on the gas it stallswhe in gear not in prk its fine engin does not hesitate all new plug and plug wires truck never did this untill I put new headers and strait pipes on. When you disconect the the vacum line from the map sensor the truck runs ruff so im sure that that sensor is working but how to I check the egr silinoid. And my truck doesnt have a maf sensor. My oil pressur is extremly low when motor is warm why is that? Could that be the cuase? Plz help this is coasting way mor money then the truck is worth
April, 5, 2009 AT 8:12 PM
Check your fuel and oil pressure then comeback with both readings in order for me to continue