Have a check engine light on 2003 Kia Spectra GS. Told by mechanic that the codes state cylinder misfire in 2 cylinders and thinks it's a blown head gasket or cracked valve. Could it be that the wires or spark plugs need to be changed? Had this type of engine light code w/ my 1997 Toyota Corolla and a new wire set, spark plugs, and distributor cap fixed the problem for about $300 vs. $2000-$2500 that the dealership wants me to spend to fix this Kia Spectra.

This problem is beyound the internet. Find a honest mechanic

bad senser or computer

Trouble Code: P0302
Does't sound like a cracked head to me I would take a look at all the vaccum lines.Also check the intake manifold and the egr system.
Cylinder 1-10 Misfire Detected
Possible Causes:


Air leak in the intake manifold, or in the EGR or EVAP system Base engine mechanical fault that affects only one cylinder Fuel delivery component fault that affects only one cylinder (e.g., a dirty fuel injector) Ignition system problem (coil or plug) in only one cylinder

mass air and tps would be 2 most common causes.

The COPS (coils) may have shorted the drivers in the PCM (computer). You should get a misfire code for each cylinder misfiring though.

Slim possibility, but very expensive unless you have a service contract.
LINCOLN: 1999-2004 Navigator
2002-2003 Blackwood
2003-2005 Aviator MERCURY: 2003-2004 Marauder
ISSUE: Some 1999-2004 Navigator, 2002-2003 Blackwood, 2003-2005 Aviator, 2003-2004 Marauder and 2003-2004 Mustang vehicles built before 12/19/2004 equipped with 4.6L 4V/5.4 4V engine may exhibit a runs rough, lacks power, and engine misfire, prompted by a MIL light and DTC codes P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308, and P0316.
ACTION: Diagnose engine for engine misfire concern. If diagnostics determine an engine misfire which is characterized by leakage through exhaust valve(s), only replace the affected cylinder head(s).
SERVICE PROCEDURE FOR VEHICLES WITH RUNS ROUGH/MISFIRE CONDITION:

1. Perform relative compression check on all cylinders. If abnormal, check cylinder leakage and actual compression for "low" cylinders refer to Workshop Manual (WSM), Section 303-00.
2. If leakage/compression check indicates a valve train concern, per valve train diagnostics in WSM, Section 303-00, replace cylinder head and cam assembly, pipe plugs and timing chain tensioner, per procedure outlined in WSM, Section 303-01.
3. If cylinder leakage and compression tests are inconclusive, perform misfire diagnostic, per TSB 05-22-8. NOTE: DO NOT TRANSFER SPARK PLUGS. INSTALL NEW SPARK PLUGS IN REPLACEMENT CYLINDER HEAD AND CAM ASSEMBLY. NOTE: THE ENGINE MISFIRE CONCERN IS TYPICALLY EXHIBITED ON THE LEFT HAND CYLINDER HEAD AND RARELY ON THE RIGHT HAND CYLINDER HEAD. UNLESS CONFIRMED, THE RIGHT HAND CYLINDER HEAD SHOULD NOT BE REPLACED AS AN "EXTRA MEASURE" SERVICE PRECAUTION. NOTE: THE REPLACEMENT CYLINDER HEAD WILL NOT IMPROVE OR REDUCE ENGINE HORSEPOWER OR TORQUE ABOVE ADVERTISED LEVELS.
   

Unless your computer in your car is faulty... the check engine light came on because it, or one of your vehicle's many sensors detected something within your vehicle was not operating under preset factory conditions. Fortunately, the error code that was extracted was indeed a cylinder # 1 misfire, which is fairly basic. Could be a bad spark plug, wire, etc. or you may have gotten some condensation inside the plug boot. Your mechanic did indeed clear the code, but drive it for awhile and see if it repeats. Normally with a cylinder misfire, you'll notice a small stutter when you accelerate or idle. If your Check Engine light returns, have the codes extracted once more. If the same cylinder is misfiring, have him replace the spark plug and wires.

http://www.kiatechinfo.com/index.asp

Good source for Kia its free to register NO STRINGS

the purge valve i believe is located near your gas tank unless theyve moved it i should look like a little canister cyclinder shaped. both codes could be set off by the same problem. try replacing the valve.

Hello, my name is Mario.

1. Disconnect battery negative cable.
2. Drain engine coolant
3. Remove bolt and nut for thermostat housing
4. Remove the old thermostat
5. Put a new thermostat and gasket (Install thermostat into cylinder head with jiggle pin positioned up.)
6. Place thermostat housing
7. Fill radiator with engine coolant
8. Connect battery negative cable
9. Start engine and check for leaks.

Good luck