Shes acting...funky.

Stephens'MSI · 10-11-2005, 11:50 AM

My car (84 NA) is acting rather odd as of late. When the revs hit about 3-4k rpms in any gear it stutters and jerks forward, like a sudden loss of power. I noticed this first while passing a semi on a 2 lane highway. Sometimes, however, it works perfectly fine with no power loss to speak of. I have already scheduled an oxygen sensor replacement, as that they havent been changed since ive owned the car. (since 2001) Could this be the source of the problem? Or perhaps a vaccum hose leak? Possibly fuel injectors? (I have a new fuel pump + filter)Or is it something more sinister? Ive recently put some techron additive in the car to try to clean it out, and It is still acting odd and losing power. Any ideas or advice would certainly be welcomed.

Thanks,
Stephen

princetonprep17 · 10-11-2005, 01:26 PM

Is it only under heavy loads on the freeway? I had the same thing happen to me while on the freeway I would experience something like a power loss and then it would come back on. Nothing out of the ordinary on the gauges. Pull all of your plugs, I'm willing to bet one of them is soaked with oil. Bad valve stem seal I believe is what mine ended up being. ABout $1500 job as the head and everything else has to come off. Let me know what you find when you get around to pulling those plugs. IF they arent in a puddle of oil then disregard everything I've said as it's just my .02

3sonfather · 10-11-2005, 02:58 PM

Can you add some more details to the symptom. Does the acceleration recover or does it completely bog down under full throttle. Can you 'nurse' it into higher rpm? I have a similar problem. What recent maintenance have you had that may coincide with your observation?

princetonprep17 · 10-11-2005, 03:07 PM

When mine was doing it I would be on the freeway and travelling along at around 75. With my foot firmly on the gas pedal maintaining a constant speed my car would surge, like I took my foot completely off the gas pedal, for about 3 seconds and then be fine again. When you press the accelerater it would not go any faster but felt like it was bogging down under the load.

Dougster · 10-11-2005, 03:12 PM

Has it been doing it since the fuel pump/filter change?
Check all connections?

XxKHxX · 10-11-2005, 05:38 PM

i woudl go with copper plugs...with the platinum +4's, they overheat at higher rpms, thus loss of power. i had them in my 84' 944 for a couple months, then heard the bad news and switched em out right away.

Stephens'MSI · 10-11-2005, 07:18 PM

Last time i checked the plugs (a week or so ago) they were fine. Im not sure if it will recover if i stay on the throttle, as that i dont know what might explode/fly off/melt if I persist. I will go ahead and buy some new plugs, just in case. Are the denso's worth their price? And yes, it has done it since the fuel pump and filter change, and as far as I know the connections are sound. If you have the car in nuetral and rev it you can nurse it to higher RPMs, I didt go nuts with it or anything and kept it to around 4500.

thanks for the help guys.

Stephens'MSI · 10-11-2005, 07:33 PM

I forgot to add that it smells like gas/exhaust fumes after it happens.

Thanks

sherald · 10-12-2005, 01:19 AM

Hey mine just was doing the same type of thing. It would stumble between 3 and 4k then once I got past 4k it would level out again.

Turned out to be a very dirty throtle body.

Dougster · 10-12-2005, 08:57 AM

Quote:

Originally posted by Stephens'MSI
I forgot to add that it smells like gas/exhaust fumes after it happens.

Thanks

Sounds like the area to focus on then...

Trevor · 10-12-2005, 03:35 PM

Hi, a little ot, but I'm down at Southern in Carbondale, where do you go for maint. ?

3sonfather · 10-13-2005, 08:44 AM

I'd like to see you resolve this problem (for my benefit and others). There are many places to consider the source of this problem. In my case (bogs down completely past 4,200 rpm but I can nurse it to about 5k), it would be easier to list the things I haven't checked or changed which range from a complete engine rebuild to new fuel pump/filter/regulator, tps, afm. The only other likely source is DME or fuel injectors. If your hesitation is only within 3,500 to 4k rpm and then you get normal acceleration, then it sounds like you have a dead spot in your afm wiper. This may be corrected by shifting the wiper arm (search other postings). I would dismiss the spark plug comment unless your running the wrong type altogether.

Slam · 10-13-2005, 01:50 PM

Throttle switch? Unplug it, drive the car and see if the problem goes away.

Stephens'MSI · 10-18-2005, 07:01 PM

I've been a bit busy lately so i havent had time to check the replies to this post. I started my car on friday of last week and the piping connected to the cat came apart. So, for about 3 days my car sounded like it was actually kinda mean. This was fun untill it acted as a sort of "cop call" (apparantly they are in season) and they flocked to me in droves. Today however, $400 dollars later, I bought this whole exhaust system with a new cat - it turns out that my old one was around 70% clogged. This however didt fix much of anything, except that I no longer smell exhaust. (And the flowmaster sounds kinda cool - just a little louder than stock while cruising, but at higher RPMS im betting that the people you passed would know that your in a hurry.) So, now im changing the O2 sensor when I get a chance, and checking the plugs and such. Im also going to clean out the throttle body as time (and demanding professors) permit. Im going to look into the other ideas, involving the wiper and the throttle switch thingy. (im hardley a gear head, i just know enough to impress rice boys that have "twin-tubo-rotary powered ford mustang gt-r's with V-TEC") I will, however, keep everyone posted. As for where do I get my car fixed in SI, I used to go to this place in Mt Vernon that had a mechanic that had worked on 944 cup cars. He moved away though, put I still go to the same shop. From what I've been told working on a 944 is not all that insane - only a few metric tools are needed and a good amount of common sense engine wise. (keep in mind that I mean basic up-keep.) For all the expensive things (timing belts, water pump, and ,most recently, transmission swap) I just ask/make my uncle do it, as that he is one of those odd guys that like to take things apart and put them back together. (o yeah, and he's been a mechanic for 30 years) Problem with that, SIU student guy whos' name ive forgotton, is that he lives around 400 miles away and im sure that he would charge you money. Sorry I couldt be more help.

Stephen

Izzy · 10-18-2005, 08:53 PM

possible vacuum leak, intake manifold gasket.