GMC ENVOY 1999

[a***@gmail.com]

On my 1999 GMC ENVOY 180,000 i keep getting P0301 misfire code. Things i changed spark plugs 3 times,all cords, evap canister, evap purge solenoid, ignition coil, distributor cap and rotor. Cleaned EGR valve. Car is still idling rough (not as bad as before) and P0301 still comes up?
What else can I do????
Any suggestions I don't have much money. So I'm DIY-ing it with a small budget. Need it to pass emission.
Thanks.

[Paul in Houston TX]

Post by a***@gmail.com
On my 1999 GMC ENVOY 180,000 i keep getting P0301 misfire code. Things i changed spark
plugs 3 times,all cords, evap canister, evap purge solenoid, ignition coil, distributor
cap and rotor. Cleaned EGR valve. Car is still idling rough (not as bad as before) and
P0301 still comes up? What else can I do???? Any suggestions I don't have much money.
So I'm DIY-ing it with a small budget. Need it to pass emission. Thanks

No one reads alt.gm anymore.
Added rec.autos.tech.

Check for vac leaks... hoses, manifold, etc.
Take a look at the injectors.

[Steve W.]

Post by Paul in Houston TX

Post by a***@gmail.com
On my 1999 GMC ENVOY 180,000 i keep getting P0301 misfire code. Things i changed spark
plugs 3 times,all cords, evap canister, evap purge solenoid, ignition coil, distributor
cap and rotor. Cleaned EGR valve. Car is still idling rough (not as bad as before) and
P0301 still comes up? What else can I do???? Any suggestions I don't have much money.
So I'm DIY-ing it with a small budget. Need it to pass emission. Thanks

No one reads alt.gm anymore.
Added rec.autos.tech.
Check for vac leaks... hoses, manifold, etc.
Take a look at the injectors.

Vacuum leak is possible but won't usually cause a single cylinder miss.
Swap the injector to a different cylinder, they are known for shorting
internally, if the miss moves replace the injector.
If it doesn't move run a compression test and a leakdown test on it to
be sure you don't have a burnt valve or mechanical problem, both tools
are available as rentals.

If you want more exposure visit www.2carpros.com and post the info and
question there.