Misfire and rough idle after cleaning throttle body...

[montana_jeepn]

I removed my throttle body, cleaned it, and reinstalled. I am now receiving misfire codes PO300 through P306....every cylinder. I discovered some vacuum leaks which I think I fixed temporarily (trimming the end where they were cracked and reinstalling)....but what do you think it could be? I was pretty liberal with the cleaner....could I have killed my TPS or IAC?

 

[shootmymime]

I removed my throttle body, cleaned it, and reinstalled. I am now receiving misfire codes PO300 through P306....every cylinder. I discovered some vacuum leaks which I think I fixed temporarily (trimming the end where they were cracked and reinstalling)....but what do you think it could be? I was pretty liberal with the cleaner....could I have killed my TPS or IAC?

keep driving it, it should go away and get everything cleaned back out and dry up. give it a bit. also you can pull the efi fuse under the hood for a min and it will reset the codes.

 

[hopdup]

I don't believe the gasket is reuseable. Did you replace it? I would pull your number 6 plug & inspect it. It wouldn't hurt to pull all the plugs & clean them. Also inspect the continuity of the number 6 plug wire. Always clear codes with scan tool. You can pull fuses or disconnect battery but it's not good practice.

 

[Doc2012]

If you're getting P0301-P0306, you hooked shit up wrong, more than likely.

Check, recheck, and check again everything is on there right, and run to the right spot.

 

[montana_jeepn]

Check and rechecked. Took her around the block and PO130 and PO133 showed up as well.

 

[montana_jeepn]

I don't believe the gasket is reuseable. Did you replace it? I would pull your number 6 plug & inspect it. It wouldn't hurt to pull all the plugs & clean them. Also inspect the continuity of the number 6 plug wire. Always clear codes with scan tool. You can pull fuses or disconnect battery but it's not good practice.

I replaced the intake gasket if that is the one you are referring to. I didn't remove the IAC when I cleaned the throttle body initially, but when I took it apart the second time I did reuse that gasket when I removed the IAC. I'm using a Scan Gauge II and clearing the codes that way. I haven't disconnected anything to do with the spark plug wires.

Could a leaky vacuum line cause these codes?

More likely a TPS sensor?

 

[montana_jeepn]

Oh, missed it before but also have PO171

 

[txbonds]

The P0130 could be related to your front bank oxygen sensor. I had my throttle body cleaned by a shop when I first got it and started getting the P0130 code right away. Finally replaced the O2 sensor and all is good since.

 

[PitbullRescuer]

Vacuum leak upstream of the MAF sensor (which is where you were working) would definitely cause the misfire codes. I would spend the $5 for new vacuum hoses and replace them. Also, are you sure they all went back on in the right places.

 

[hopdup]

P0171 is a lean code. You most definitely have a vacuum leak somewhere. You can use a can of carb & choke clean to find vacuum leaks. Just spray lightly around the intake, throttle body & vacuum line area. When the engine idle rises you have found your leak. The engine is pulling in the cleaner, thus enriching the air fuel mixture. That's what causes the engine rpm to rise.

 

[montana_jeepn]

You all are awesome. I appreciate the help and will let you know what I discover later this week.

 

[montana_jeepn]

Okay, this is where I stand as of now. I replaced most of the vacuum lines (did the ones around the throttle body first), replaced the TPS (scored a new factory part for $25 so I figured why not), cleaned the MAF (let it dry overnight), and at one point even reinstalled the factory intake tube (actually that was the first thing I did to no avail).

I am still getting misfires on all cylinders. None of this was happening until I took the throttle body off so I must have caused it somehow. She sounds like a cam'd sports car. lol.

Thoughts? Could a bad IAC cause misfires? I also noticed a little bit of oil in the inlet to the intake manifold near where the line from the PCV comes in. Seemed like more than should be there.

 

[TheDurk]

PLEASE:

Check your plug wiring against the diagram below. I have had several posters claim they had their wiring right until they checked this way--and suddenly their issues were solved. It's the cheapest easiest fix there is, so please do it one more time.

 

[montana_jeepn]

PLEASE:

Check your plug wiring against the diagram below. I have had several posters claim they had their wiring right until they checked this way--and suddenly their issues were solved. It's the cheapest easiest fix there is, so please do it one more time.

I'll double check, but I never took my plug wires off.

 

[montana_jeepn]

PLEASE:

Check your plug wiring against the diagram below. I have had several posters claim they had their wiring right until they checked this way--and suddenly their issues were solved. It's the cheapest easiest fix there is, so please do it one more time.

Checked the wires. They match your diagram.

 

[montana_jeepn]

While waiting for my new IAC (factory part off of Amazon for $128) I started replacing the plugs and plug wires. I went with OEM on both. Get this though, the sparks plugs were hand-tight! That can't be good. I replace two before I had to run some errands with my wife. Plugs were dirty and looked brown and white-ish. They were Bosch Double platinums.

 

[TheDurk]

While waiting for my new IAC (factory part off of Amazon for $128) I started replacing the plugs and plug wires. I went with OEM on both. Get this though, the sparks plugs were hand-tight! That can't be good. I replace two before I had to run some errands with my wife. Plugs were dirty and looked brown and white-ish. They were Bosch Double platinums.

I bet that's it then. I was definitely smelling spark issue. You may also have an IAC issue but getting the plugs right will make a huge difference, if not cure it completely. Keep my diagram for when you are done with the wires.

 

[Piney]

This is an old thread but I’ve seen lots of this exact same issue after the throttle body comes off and it has been because the air assist hose was not reconnected.
It must be an easy thing to miss. It can be other things, of course, but low idle and random misfire codes and hard starting point to the air assist hose.