Question about 1998 Ford F150 Regular Cab

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Misfire on 5 and 7

Had to change transmission because reverse went out and a cat. converter cause p420 code. when was done ran fine for a few minutes then started misfiring. changed distributor cap and still same issue. wires and cap were changed recently

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P0420 Catalyst System Efficiency Below Threshold (Bank 1), hope it can help you.
Launch X431

Posted on Jul 10, 2013


6 Suggested Answers

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

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Posted on Jan 02, 2017

  • 957 Answers

SOURCE: Misfire on 4, 5 & 6

Take your time, if its been awhile do a complete tune-up. and preliminary check a misfire can come from a defective cap and rotor, fuel and air filter. a leak in the fuel system or defective regulator.

Posted on Apr 28, 2009

  • 15 Answers

SOURCE: Misfires in Cyl. 5 and 6, after changing problem continued

white smoke indicates the engine is burning antifreeze, you could have head gasket issue, if thats the case the antifreeze is getting in the cylinders and the engine is burning it. could be a stuck exhaust valve( i doubt it). find out from ford what that code indicates, that would be a better clue than tearing into the motor

Posted on Jul 21, 2009

  • 3600 Answers

SOURCE: po 305 misfire

it is a misfire on cylinder 5 it can be caused by low fuel pressure or a defective coil or bad injector, it could also be valve adjustment on that cylinder. Please rate me for the help I have given and if you need more info just post and I Will answer.

Posted on Jul 29, 2009

  • 80 Answers

SOURCE: 2002 Ford Ranger check engine light indicating misfire

Code P0301
Ignition Coil Pack
Ignition Cable
Spark plug
Clog or dirty fuel injector
Evap canister purge valve
Engine Compression
fuel pressure

you have 3 type of engine for your truck
2.3L 4 cylinder
3.0L 6 Cylinder
4.0L 6 Cylinder

need to know that type Engine

The reason why the service light come on because it is a hard code
not a soft code.

Let me know

Posted on Sep 20, 2009

  • 220 Answers

SOURCE: 1998 windstar 3 litre number 3 misfire ,changed

did you leave your battery hooked up while you were replacing the spark plugs and coil and such? try resetting your ECM.

Posted on Jan 15, 2010

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What is causing my 02 Sub to missfire after driving it turning it off and restarting it ?

Check your fuel pressure. Unspent fuel would cool the converter. A lean fuel situation would create the glowing exhaust.

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2004 nissan xterra run great for 12 miles then misfiring,cnt get over 45 miles an hour. codes p 0733,p0420,p0430,p0328 comes up. new wires,new cap,rotor spark plugs 6 months old timming belt 6 months...

code p0733 refers to gear 3 -incorrect ration===causes---wiring---TR sensor/switch--shift solenoids---transmission mechanical fault
code p0420 refers to catalytic converter system -bank 1---efficiency below threshold===causes--cat converter--wiring--HO2s 2
code po430 refers to cat converter system bank 2--efficiency below threshold===causes--cat converter--wiring ---HO2s 2
code p0328 refers to knock sensor (KS) 1 bank 1--high input===causes--wiring short to positive--KS incorrectly tightened--KS---ECM

basically replace the cat converters as they are blocking the exhaust system and preventing your over 45mph problem
replace the TR sensor/ switch as you have not mentioned a transmission problem
Rectify the problem with the KS as it controls the air/fuel mixture setting which contributes to the car getting hot.

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Trouble Code p0420 and p1399

code po420 refers to cat converter system bank1 - efficiency below threshold===causes -- cat converter---wiring---HO2S 2
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I would want to know what the fuel pressure is on the rail. Sounds like the fuel pressure regulator has failed, or the return line to the tank is blocked.

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2002 fire bird replaced the cat converter all three sensors still getting p420 code

Are you sure that the rest of the exhaust system is not blocked (muffler)
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I have a 95 neon that runs good for about 25 minutes then acts like it has run out of gas. After a few minutes it starts back up and runs for about 10 minutes. I changed the fuel pump and it still does the...

Your explaining a stopped up exhaust. This can happen to any car. (Bannanas in the tailpipe) The old car can have a bad cat. converter thats in the exhaust system. This part needs help to fail, so after the cat. is changed the car has to be checked to find the cause of the failure as the new one will fail and their not cheap. Misfireing , burning oil , or antifreeze, EGR valve not working or some sheade tree hotrodding can make converters fail too. It's illegal to remove a converter and not put the right part back on, Theres jail time and big fines for those that get caught.

Oct 12, 2009 | 1995 Dodge Neon

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I keep getting this p420 code of and on , also when my truck was only a couple of years old i had to replace the cataletic converters ,the mech told me bad gas ,is this true? and is this part of my p420...

Code p420 is a code for catalytic converter enefficiency. This can be caused by a few problems. The vehicle uses two sensors one before and one after the cat. The sensors determine how well the cat is doing its job based on how much oxygen is sensed in the air based on the rule of thumb of 21% in our atmosphere. You mentioned that these were replaced once before, and i hate to knock another technicians work without seeing it but it could be possible that the cats he installed were not OEM parts and just a generic. You can get this code from using a non vehicle specific part like that, aseasily as you can get it from a faulty pre or post cat o2 sensor.
best thing i can suggest is getting the car on the scanner and having a buddy drive it on the highway at a steady rpm, watch the 02 sensors and see if there is erattic movement or sticking, from there we can findthe next step, and FYI all catalytic converters come with a Federally Mandated Warranty period of 8 years 80,000 miles, so dont ever pay for new ones again.

Aug 27, 2009 | 2005 Dodge Ram 1500

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1998 CIVIC P420 CODE

the cat is bilt into manafold and the sencer is just up abuve it

Jun 19, 2008 | 1998 Honda Civic

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