Last post on Apr 13, 2013 at 7:01 PM
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Volkswagen Jetta, Engine, Sedan
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#263 of 292 Rough idle, Muffled Exhaust, even w/ new plugs, wires, and ignition coil
Dec 01, 2009 (6:40 pm)
2002 VW Jetta 2.0 4 cyl 135,000 miles
Car started to sound like it had a bad muffler.
Two weeks ago check engine light came on and flashed. Garage stated wires were bad and plugs fouled so I had them replaced. They recommended the ignition coil as well but at $400 for just the part I pasted. Car ran fine.
2 days later the check engine light came on again. I replaced the ignition coil myself. Easy repair. Put the plug wires back as they came out, number 1 in A 2 in B 3 in C 4 in D.
Car seemed to be running fine, expected the check engine light to reset after 100 miles and it did not. Still makes that sound if you hit the gas when it is in neutral like the exhaust has a chest cold (only way I can think of describing it)
There was a recall on the catalytic converter and was replaced at 85K. Took the car to auto zone and they said the code was for a bad ignition coil still. Unless the garage put the wires back in coil in the wrong, order I am out of ideas. I have the single ignition coil unit not four separate ones like on a V6.
Out of ideas...O2 Sensors maybe? I did recently change my brand oil of oil from Mobile 1 Full Syn to Castrol Edge Full Syn. Probably grasping at straws at this point
#264 of 292 Re: Rough idle, Muffled Exhaust, even w/ new plugs, wires, and ignition coil [dp2226]
Dec 01, 2009 (7:12 pm)
What SPECIFICALLY was the code they pulled out of your car?
I am not sure there is a code that says "Bad ignition coil".... It sure looks to me that all of these folks are mis-interpeting what the code is telling them.... As witnessed by the fact that none of them have successfully diagnosed the problem yet.
You did a great job of describing the problem and the steps you have taken thus far... perhaps if you tell us the SPECIFIC code, we may be able to help troubleshoot.
The MAF (MassAirFlow) sensor on your engine may be going bad. An easy way to check the MAF sensor is to pop the electrical connector from it and let it dangle. (yes - this WILL cause the CEL to light up) Then start engine and drive for a few days. If things are better, then suspect the MAF is bad.
Also, check the color of your ECT (Engine Coolant Tempararure) sensor. If it is not GREEN, replace it. (about $15 and the Oring) The ECT of that vintage are KNOWN to go bad and VW came out with a better design which is colored GREEN so it is easy to tell if you have the newer one installed.
You cannot tell if the ECT is bad by looking at the guage on the dash because the ECT has 2 sensors within in.... 1 for the dashboard and the other for the EngineComputer. If the computer "thinks" that the engine is always cold, your engine may run like crp.
Also, you should make certain that the engine is MECHANICALY sound. A compression-test may be a good way to validate that you do not have troubles with valves. (which could also cause this problem)
#265 of 292 Re: Rough idle, Muffled Exhaust, even w/ new plugs, wires, and ignition coil [dp2226]
Dec 02, 2009 (8:36 am)
you should not had paid for the coil there is a pending law suite against VW for the coils in jetta and golf also audi that uses same coil you should have done more research in the lemon laws.if you have any ?'s e-mail me.
#266 of 292 Re: Rough idle, Muffled Exhaust, even w/ new plugs, wires, and ignition coil [dp2226]
Dec 02, 2009 (10:42 am)
Hi dp2226: It sounds like bpeebles has a better grasp than anyone of the possible issues here, but I have a footnote to 77camaro's advice. I believe he/she is correct regarding the coil lawsuit, but I also believe that this was resolved with VW agreeing to a replacement of ALL coils of that vintage, and including reimbursement for repairs of defective coils previously replaced (with appropriate documentation). I had similar issues with my '02 Passat 1.8T. Get this resolved asap, as failure to do so could ruin your cat converter, a $700 repair item. Good luck. vwdawg/audiphile1
#267 of 292 Re: Rough idle, Muffled Exhaust, even w/ new plugs, wires, and ignition coil [77camaro]
Dec 02, 2009 (1:40 pm)
Are you CERTIAN you are not thinking about the about COP (Coil On Plug) ignition-units on the which had a bad batch get into the mix? The status of the those COP units was ONLY if one failed, then VW would replace it.
The 2.0 engine that we are talking about here DOES NOT have COP ignition-units.
If there is something "pending" which you are refering to besides the COP units... please append some reference URLS that support that statement. I would be very interested to review those documents because both of my daughters have VWs of that vintage with 2.0L engines.
#268 of 292 Re: Rough idle, Muffled Exhaust, even w/ new plugs, wires, and ignition coil [bpeebles]
Dec 03, 2009 (9:44 am)
bpeebles: Not sure which system 77camaro was referring to, but I was referring to the 1.8T, which DOES use the COPs. I'm not familiar with the 2002 2.0, but I assume it's a NON-turbo, which would not use the COP units, right? If that engine does not use COPs, then you are very likely correct...I have not heard of any pending suits for the non-COP systems. vwdawg/audiphile1
#269 of 292 Re: Rough idle, Muffled Exhaust, even w/ new plugs, wires, and ignition coi
Dec 03, 2009 (10:00 am)
BTW, there is now a recall on the ignition coils for the 2.5 engine...not sure what years are included, we have a 2005.
#270 of 292 Re: Rough idle, Muffled Exhaust, even w/ new plugs, wires, and ignition coi [jeffyscott]
Dec 03, 2009 (11:54 am)
there is a site you can check for recalls- lemon law volkswagen ignition coil when you go here the left margin has where you can plug in year make model engine etc. they will tell you of pending suites or if recall has been resolved good luck the dealer still has not released coils to me do to pending suit car has been down for over a month tired of putting used coils just ordered set of bremi's I just registered in suite to get reimbursed.
#271 of 292 Re: Rough idle, Muffled Exhaust, even w/ new plugs, wires, and ignition coi [jeffyscott]
Dec 03, 2009 (7:05 pm)
The 2.5L engine uses COP (Coil On Plug) ignition units. Apparently, these COP units have been troublesome for VW.
There is a reason that COP units are considerd high-tech.... each indivudual ignition-unit is plugged DIRECTLY into the top of the sparkplug. This means the COP unit must endure extremely high heat from the cylinder head. Heat and electronics do not mix well. (The heat always wins in the end)