xsboost90

maybe im just new to the 44 cars, but it seems that my car has some things that just kinda get on my nerves. I love the look, it handles great, and it fits me like a glove. Get on the gas, now that ive tightened the cable abit, and she takes off, but upon decent, the engine seems to stumble and shake alittle. Im thinking maybe its just because of those funky balance shafts, but maybe not. How many of you have this same thing, and is that a factory option, or is my engine running wrong.

89 2.7l 944.

SidViscous

Assuming the 2.7 is similar to the 2.5 there is a stumble as teh engine goes to idle. Danno says cleaning one of the trottle sensors fixes it, and another guy says it's a software problem and sells a chip to fix it.

If your having problems at idle, it could be the motor mounts, but I also got greatly improved idle by hooking up all the vacumn hoses and running suplementary grounds to the block and then to the front mounting points on the Frame rails.

slevy951

Sid and all-

I thought the software fix was only for the early cars (83-85.5). Maybe a bad idle stabilizer valve??

SidViscous

Could be.

Got to tell you. It's kind of grown on me. after being on throttle coming down can be so quite I think maybe she stalled. That little shudder tells me. Hey everything is going fine.

But I'm wierd.

Waterguy

One possibility comes to mind: throttle position switch (TPS). The TPS has an idle switch to tell the computer when the throttle is fully closed. When I bought my car, I found that the "stupid mechanic" had left slack in the the throttle cable. I adjusted it out, and found that the car would now buck/stumble during off-throttle deceleration. What happened was that the TPS idle switch alternated between idle (900 rpm) and off idle (1400 rpm), which caused the stumbling. I posted my problem on Rennlist, got advice, adjusted my throttle cable to put some slack back in (yeah, that does suck a bit!), and my off-throttle stumble went away. Turns out the mechanic wasn't stupid.

MAS

If you are referring to the stumble (or hesitation) as the throttle returns to idle (at about 1300 rpms)... apparently that's normal, and has something to do emissions control with the stock chip programming (I've no idea why).

However, if you are talking about stumbling under acceleration, then then it could easily be one, or more sparkplug that is dirty/fouled (or whetever). Sparkplug cables (particularly the boots) are another place to look. But I'd check the plugs first. BTW, if you haven't had the plugs changed recently, this would be a good time to changes them anyway.

-MAS

xsboost90

yeah, i need to do a full tune up, it had a timing belt recently,but i would like to do the plugs, wires, filters and all...it seems to have calmed down a bit since ive been driving it, or maybe im just used to it now...i do remember something about a fuel cut off in the chip when decelling to keep from flooding or something, could be that.- thanks everyone