# Random sputtering and bogging on 92 MK2 8V Jetta PLS HLP!!!



## ThaDon55 (Nov 20, 2010)

Ok, so heres the run down. I have a 92 MK2 Jetta digifant with 229k miles on it. I just recently started having this issue where the car sputters at start up and low speeds once it's driven for a bit or on really hot days. It started about a few days ago and back fired twice since then. Once the first day and then again today. It seems like the car is struggling for fuel almost. I've replace coolant temp sensor and in tank fuel pump already. Fuel lines seem good also and replace most of if not all of my vacuum lines as well. Any thoughts on where I should be looking or checking to solve this problem? Oh yeah and I almost forgot, I just notice one of the bolts from my exhaust manifold came out. Not sure if that could be related but thought it might be an important bit of info. Also, the cat is empty so no congestion that I can think of. And lastly as the thoughts keep rolling in...lol Anyone know how to get to the exhaust manifold, I'm trying to replace it with a header and performance cat. Thanks in advance!!!


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## Fat Rabbit (Nov 18, 2001)

One of the failure modes of the main pump is to get lazy when hot. You might want to check the fuel pressure at the fuel rail. Borrow or rent a fuel pressure gauge. It will clamp on to the hose barb at the end of the fuel rail after you remove a small bolt that seals the barb. You should have around 35-40 PSI with the engine running.

You should replace the exhaust manifold bolt and see if you can get it to seal up if it is sucking air. The air could cause confusion with the O2 sensor if air is sucked into the exhaust system. To access the exhaust manifold I remove the intake manifold from the engine and the downpipe from the manifold -- then it is a matter of trying to remove the manifold nuts from above and below. Typically a few of the studs will break -- sometimes I end up removing the head to get better access to remove the broken studs. Since you are in LA you might have better luck with the studs than I do here in the rust belt. FR


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## ThaDon55 (Nov 20, 2010)

Dude you're awesome. That was great info. I'll go to work on that ASAP and let u know what I find. Thanks for the quick response.


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## cramletram (Jul 11, 2011)

Did this work? I'm having the same issue.


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## ThaDon55 (Nov 20, 2010)

So the crazy thing is I can't find a single mechanic willing to test my fuel pressure and every one that I've talked to that have looked at the car tell me something different. I took it to my mom 
's mechanic but he specializes in Mercedes and he gave me some tips. The first was he check my distributor cap and it was fried at the coil input. I replaced it last night and so far so good. Going to a friend who's mechanic to have him look it over as well but so far so good. It seems when most mechanics see you know how to fix but not diagnose your car they aren't interested in getting involved. I even asked them to do the work and I'll pay them. It's sad, my mothers mechanic was more like you don't need me to fix it you know how to do things. He just give's me advice then tells me how to do them myself so i can save the money. People are strange sometimes...lol I'll keep this up to date once I have confirmation!


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## ThaDon55 (Nov 20, 2010)

So here's the word. The distributor cap has solved the problem. I went from potentially hundreds to $20.... Lmao Problem solved!!!


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