Engine Running Bad Sometimes

I have a 92 Tsi AWD. It has a K&N and I recently cut off the muffler. I bought this car about 3 months ago and it had this problem before I put on the K&N filter and cut off the muffler. Most of the time the engine runs good except at full throttle when it gets around 5 or 6k rpms. It sounds like pop, pop, pop. When I had the muffler on it sounded like puff, puff, puff. The engine almost quites accelerating, so I'll shift then it starts accelerating smoothly again. It doesn't do it every time, but it happens quit a bit. A few weeks ago I put in NGK BPR6ES spark plugs. The car ran really well for about 3 days. Then it started having the same problems again. Also, sometimes on cold mornings the engine will not accelerate smoothly at part throttle and low rpms. I'm thinking it could be the oxygen sensor, but I'm no expert. So, if you guys and girls have any suggestions please let me know.

[At-Least-It's-An-Evo]

try swapping wires. Mine did that, then i swapped plugs; that helped a tiny bit. Then it started up again.. wires were the key.

I did swap the wires at the same time I swapped the plugs.

[TheBlizzard]

From what you are describing you could have a number of problems. Have you tested for boost leaks at all? If it isn't that you could be running out of fuel. Not sure why it would be doing this since you don't have many mods but you could have a part on its way out. But I would definetly check for boost leaks next if you have replaced your plugs and wires. The pop, pop, pop noise you are getting is either the car running rich or lean, you just have to figure out which one it is.

By the way, are you getting a check enging light at all? If you are find somebody with a logger and a 1G cable and pull the code.

[santa]

HEAD GASKET......like me lol sounds like my car but my pop pop pop sounds like a gun going off...gotta love open 3inch d/p!!!

I havn't checked for boost leaks yet. Would I do that by making sure all the hoses are on tight, or is there a better way? There are no check engine lights on.

If it is the head gasket, would I find that out by checking the compression pressure?

[MustGoFaster]

What are you gapping the plugs at?

[john]

Yeah, I would check the plug gaps first. A boost leak test is different than a compression test. Vfaq.com shows how to make a boost leak tester. All you do is pump/compress air into it and listen for leaks. If you find any you fix them.

When I installed the plugs they were gapped at .030.

[MustGoFaster]

Originally posted by 92TSi@Dec 27 2003, 01:09 AM
When I installed the plugs they were gapped at .030.

Well, try knocking it down to, .028, not a bid diff but every little bit helps when your troubleshooting.

[CVD]

Originally posted by santa@Dec 26 2003, 03:49 PM
HEAD GASKET......like me lol sounds like my car but my pop pop pop sounds like a gun going off...gotta love open 3inch d/p!!!

Usually a head gasket problem will not cause the car to run any different. Especially a small head gasket problem like yours or mine. A completely blown exhaust-smoke-show head gasket might make a car run differently, but thats about it.

[TheBlizzard]

Originally posted by 92TSi@Dec 26 2003, 06:18 PM
I havn't checked for boost leaks yet. Would I do that by making sure all the hoses are on tight, or is there a better way? There are no check engine lights on.

If it is the head gasket, would I find that out by checking the compression pressure?

You could make sure that all your connections are tight. But the proper way to boost leak test is to make a boost leak tester which you hook up and put pressure on your system and then see if its leaking (kind of like putting boost into your engine when its off). If you need one I think there is one laying around here that JET made for his car. PM him and see if he still has it, you could come over and borrow it if you want. I live in Woodbury.

If your plugs are gapped to .030 you should be fine at stock boost levels, the only time you should have to go to .028 is when you are running 15psi and above. You could try it but I don't think you will have much luck fixing your problem. If you plug gapping was the problem it would be missing long before you hit 5k or 6k rpm, it would miss as soon as you hitting full boost which I hope would be long before that.

Check all your IC piping and even check your IC itself. They have been known to get little holes in them and they are hard to diagnose. Other than that you are going to have to pressurize your system and make sure its tight. Thats were I would go next.

If thats not it you likely have a fuel supply problem somewhere.

If you need one I think there is one laying around here that JET made for his car. PM him and see if he still has it, you could come over and borrow it if you want. I live in Woodbury.

I live in Des Moines, which probably isn't very close. Otherwise, I would borrow it.

Yesturday, I took off the air filter assembly. I noticed there was oil in the intake tube that goes from the MAF to the turbo. It looked like motor oil. Does anyone know what would cause that?

[Halon]

most likely blow by from your head. its normal since u prolly still have a rubber hose going from the valve cover to the intake. you can fix that by getting a catch can, just so happens QPR is gunna be designing their own, you could prolly get one from them when they are done. but your PUT PUT, hmmm... im not sure, im not in the mood to think what so ever right now, so just do what they said!

[MATCHBX]

I had this same problem right after i swapped my wires. It was one plug wire that would pop off of the coilpack. I pushed it on there a little harder and haven't had the problem since.

Just as a side note, I went to drive my car last nite and it started popping as soon as I got into boost. I figured it was misfiring so I turned around and drove home. I went and got new plugs today and the problem was fixed. They had worn down on the electrode so they had a gap of around .043". The new ones were gapped at .038" when I opened up the box. I gapped them to .030". The guy behind the counter said they should be gapped right from the factory. That's why I never go by what they say behind the counter as far as gapping goes. I always double check and re-gap them. Of course I have quite a few miles on those old plugs.

[adam_murphy]

dont stone me for saying this but check your injectors... i bought a 94 GSX and on the 6 bolt i didnt realize it but it had 3 450's and 1 390... that caused my car to not accellorate over 6k rpms and caused me to blow it up again :S just making sure you cover all the bases