Shaking bug

[funky]

Last week my car was running ragged, got codes PO327, P0420, P0300. Replaced the passenger side knock sensor, installed new plugs and new coil packs. Ran car for 50 miles and it ran great. No engine light on. Driving home last night, my engine light started flashing and started running rough especially around 2100-2500 RPM's. I will go get the codes at Autozone this morning and keep you posted. Any thoughts or suggestions? The car is running rough now where it would jerk every so often before I replaced these parts,

[PRM502STREET]

Plugged up?
Catalytic converter that is.
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[funky]

I will see what codes I get shortly and post back. I don't have emissions here in Colorado, can you delete the Cat Converter? What does that do to the computer (O2 sensors, etc.)

[jfoj]

Converters were known problems in these cars, only the 2.0l had a recall, not the 1.8t. My 2nd converter with only about 20k miles sounds like a can a marbles.

See this post, I have the replacement here waiting to be installed. Looks pretty good for under $250.

Gutted Out Cat

[IndyTom]

Originally Posted by funky

I will see what codes I get shortly and post back. I don't have emissions here in Colorado, can you delete the Cat Converter? What does that do to the computer (O2 sensors, etc.)

Post the codes. Wondering what it could be myself. I still have my original CAT on my 160k 1.8 Beetle. So far so good but if it goes bad I will delete it and us a non-Fouler on the post Cat O2 sensor. that way it won't throw a cell.

[funky]

So I just had Autozone read my codes and came up with P0300 & P0301. As mentioned earlier, I just put new plugs and coil packs & knock sensor. It ran great for about 50 miles now running real rough. Any ideas as what to try to find out the culprit?

[funky]

On another note, I asked Autozone to set the gap of the plugs to .32 as I did not have the tool. They said they were at .32 and did not change anything. Could a too big of gap or too small cause the missfires? Does anybody know what a stock NGK come set at?

[IndyTom]

May I ask what spark plugs you replaced the old ones with and did you check the gap to be no more than .032? The 1.8 is very particular about spark plugs. It doesn't like BOSCH plugs at all. I would recommend only NGK OEM or the Iridium plugs.
I use these on my car and they work great!
NGK (6418) BKR6EIX Iridium IX Spark Plug, Pack of 1 : Amazon.com : Automotive

Check Pep Boys, that's where I got mine and they usually have them on Sale for about $6.95 a plug.

Another thing you might try is check your MAF sensor. Take it off and get some MAF sensor cleaner and carefully clean it. It can cause those codes.
Also verify your Fuel pressure. How long since you changed fuel filter?

[IndyTom]

Originally Posted by funky

On another note, I asked Autozone to set the gap of the plugs to .32 as I did not have the tool. They said they were at .32 and did not change anything. Could a too big of gap or too small cause the missfires? Does anybody know what a stock NGK come set at?

I would never assume that they are set properly from the factory. Always check the gap prior to installation.
Most of those NGK plugs that I have checked were always much larger of a gap than needed. Usually a little smaller gap will not cause this issue but a larger gap will.
I actually kept the gap of the Iridium plugs at .028 which is recommended if your car is chipped or tuned and they run great. No misfires ever. I actually wouldn't gap Iridium plugs. They very thin electrode breaks if you look at it wrong. It conducts electricity much better than platinum but gapping a Iridium plug is never a good idea. And don't let Autozone idiots gap your plugs. I let them do it once and they broke three of the 4 prongs right off. Nitwits.
Just get a little spark plug tool and do it yourself. They don't cost more than a couple of bucks.
I am surprised Autozone even had your NGK OEM plugs. Here they don't carry them at all. They wanted to sell me Autolite or Bosch and I told them no thanks. Went to Pep Boys and got the Iridium plugs and they worked GREAT.

[funky]

The plugs are NGK and the same number that I have used on the previous 3 changes. I will try cleaning the MAF but wouldn't the MAF throw a code if it was faulty? I have not changed my fuel filter in probably 2-3 years. I will also try that.

[funky]

I will go get a gap tool and remove and check them all tonight. Funny how after I installed the knock sensor, plugs and 4 coil packs, it started right up an purred and ran great for 50 or so miles. You would think that if the gap was off, it should pick up on it as soon as you crank it over.

[IndyTom]

Originally Posted by funky

I will go get a gap tool and remove and check them all tonight. Funny how after I installed the knock sensor, plugs and 4 coil packs, it started right up an purred and ran great for 50 or so miles. You would think that if the gap was off, it should pick up on it as soon as you crank it over.

Is the Number of the NGK plugs PFR6Q ? Those are the recommended OEM type plugs and yes according to NGK they are pregapped at .032 from the factory.

The MAF wouldn't necessarily throw a code saying it is faulty. It can send incorrect signals to the ECU which in turn can cause a misfire. You can also try to swap coil packs from Cylinder one to Cylinder 4 and see if you get the P0301 code back or if it has changed to P0304. In which case you may have a bad Coil Pack (even if it is new) If you bought it from Autozone it wouldn't surprise me. China is their main source of imports for parts

I assume you already checked for any vacuum leaks or cracks in any of the plastic hoses and rubber hoses?

[IndyTom]

I found this link of someone that had the same exact problem.

have 2001 beetle 1.8t error code p0300,0p301p0302 changed - JustAnswer

[funky]

Not sure of the spark plug number off hand but will check. I have not done a smoke test to see if I have any vacuum leaks but replace a few of them (but not all) recently. I have tried to see if I could see any obvious holes but did not. I will try a cleaning of the MAF along with verifying the spark plug gap. I could also try my old coil pack in cylinder 1 to see if that clears it up. I think they were still good, just changed them when I did the plugs

[IndyTom]

Originally Posted by funky

Not sure of the spark plug number off hand but will check. I have not done a smoke test to see if I have any vacuum leaks but replace a few of them (but not all) recently. I have tried to see if I could see any obvious holes but did not. I will try a cleaning of the MAF along with verifying the spark plug gap. I could also try my old coil pack in cylinder 1 to see if that clears it up. I think they were still good, just changed them when I did the plugs

Sounds like a plan!

Let us know how everything works out.

[funky]

I will keep you posted and really appreciate you taking the time. I owe you a cold one!!

[funky]

So when I got home last night I pulled all plugs and coils to check the spark plug gap. Everyone was set at about .046. I re-gapped them to .032. Sine I was having misfires in cylinder 1, I took my old coil pak and put it back in cyl. 1. Connected the battery again and it started right up and purred like a kitten. Drove 20 miles to work this morning and it ran like a new car. No dash lights present. Last time it ran for 50 miles and went to hell after that so we will see. Not sure if it was the gap issue or a bad "new" coil pack. I will run it for a few days and see and then I will put that new coil pack back into cyl. 1 to see if that was the issue. I had asked Autozone to put the gap at .032 and they said they all checked out at .032. Yea right. I am keeping my fingers crossed that this did the trick cause she runnin great right now. Indytom, thanks so much for all the help, I really appreciate it. This board is awesome and I will keep you posted.

[PRM502STREET]

Good deal. Woot woot banana!

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[IndyTom]

Originally Posted by funky

So when I got home last night I pulled all plugs and coils to check the spark plug gap. Everyone was set at about .046. I re-gapped them to .032. Sine I was having misfires in cylinder 1, I took my old coil pak and put it back in cyl. 1. Connected the battery again and it started right up and purred like a kitten. Drove 20 miles to work this morning and it ran like a new car. No dash lights present. Last time it ran for 50 miles and went to hell after that so we will see. Not sure if it was the gap issue or a bad "new" coil pack. I will run it for a few days and see and then I will put that new coil pack back into cyl. 1 to see if that was the issue. I had asked Autozone to put the gap at .032 and they said they all checked out at .032. Yea right. I am keeping my fingers crossed that this did the trick cause she runnin great right now. Indytom, thanks so much for all the help, I really appreciate it. This board is awesome and I will keep you posted.

I wouldn't trust Autozone to check to see if their zipper is up yet alone if the plugs are gapped properly. More than likely the gapping issue was all that was wrong with your engine. The coil is probably fine.
Glad you got it all fixed and running again.

[esse10]

Good to hear you found the problem member funky. I was going to suggest Autolite platinums cause the last time I used NGK $6.00 jobbers my beetle threw a few missfires & codes so I went back to the $2.00 Autolite Platinum jobbers and all is good now, she purrrs like a kitten, even with this Texas gas..LOL