Codes p0171 p0303 p0325 car missing

code p0303 refers to cyl 3 misfire detected ===causes engine mechanical fault--wiring--ignition/fuel system--injector--ECT/MAF sensor--ECM
code p0316 refers to misfire detected during start up --first 1000 revs===causes --engine mechanical fault--wiring--ignition/furl system--injector
the common fault cause is ignition/ fuel system and injectors so I would be checking fuel pressure and injector systems for clean and wiring connections are good especially on no 3 injector.

Code 303 is a miss or lack of power on cylinder 3. If you know for a fact that cylinder is getting spark it could be an injector problem.
Code 420 means the catalytic converter is not performing up to standard which could be several things including the miss on cyl 3.

Hi Candy,here's a link to the P0171 code.Here's the code P0325. O n the Code P0171.it says it will have a

• detonation (spark knock) which,the first code is causing the second code to go off.

P0303 is a misfire on cylinder 3 - check the ignition and injector on that cylinder.
P0171 means engine is running lean (probably related to the above).
Start by checking the tune of the engine, verifying with a timing light that all cylinders have spark. Since these are coil over plug, swapping cylinder 2 with cylinder 3 should result in P0302 in addition to P0303 DTCs being set. If there's a problem with the VVT (Variable Valve Timing system) then there should be a DTC associated with that as well.

If you have spark, then it goes on towards a faulty injector. If both spark and fuel are present, it's possible that the VVT (Variable Valve Timing) system is freewheeling cylinder 3. Usually that implies the hydraulic lifter seals are faulty though there should be a noticeable valve tap at idle.

In any case, testing out ignition then fuel then ruling out VVT-related issues should resolve the problem completely. I have seen many of these have problems with the plumbing to the valve lifters getting clogged and that results in a dead cylinder.

cylinder 2&3 misfiring, inspect plugs if ok, mark and swap coil packs for known good ones clear codes, run eng brake torque it rev to cause missfire, repeat until check eng, lite comes on, recheck codes if changed cylinders replace coil packs if not, you have two bad injectors.

P0171 is LEAN and P0303 is misfire number 3 cyl. Its time to stop guessing and pay for a correct diagnosis. Find a shop that works on VW and has the tools to work on it. DO NOT put those Bosch Platinum Spark plugs in that Ottozone tries to sell everybody.

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You are mis fireing on cyl 1 and 3 if you replaced plugs and wires and coil this is going to be a fuel injector issue or valve issue. See if you can swap the injectors with known good cyl. and see if it changes. Or have a shop do a fuel injector service on it to see if it helps. It may be to late for the fuel injector service.

po301 thru po306 all misfire codes cylinder 1-6 remove plugs and replace them..... set the plug gap first
i suggest u replace the wires also if they never been replaced all these misfire codes can set the others and one is for the oxygen sensor ( 02s or HO2S) CIRCUT MALFUNCTION do u know how to check wireing systems
do the tune up plugs (set gap) .052-.056 change the fuel filter also. clear the codes hows it run
this info is for 98 E-250 4.2Litre
what engine do u have 4.2L or 4.6L i know it is a v-6 by the codes