95 lumina Hard shifting, tried many things,still not fixed??

[nokia]

I have a 95 3.1 lumina with 105000 miles on it, it shifts hard between 1-2 gear, and 3-4 could be smoother to, but not quite as bad as 1-2. The computer only shows a egr problem which i believe is due to a semi-clogged port going to the throttle body, and the turn signal switch under the steering wheel needs to be changed. I have replaced the tps(as this was defective), the vacuum modulator(as this was defective), both of these were purchased from napa,(yes this is a adjustable modulator and i have tried it in various different settings) i have flushed the fluid,replaced the filter and changed the trans accumulator and the pistons and orings in the accululator(which had some very minor scuffs), all three of those things have been documented to cause this particular problem that i'm having, so that's why i did those, i have also swapped out the ecm with a known good unit, i guess the next thing to do is replace the valve body, as it seems there are problems with these valve bodies, unless someone can tell me if there is something that i am missing here. I have done a pressure test and it was within the acceptable range, and i have pulled the vacuum hose from the intake manifold comming from the modulator, left the hose on the modulator and plugged the hose, i guess this causes the pressure to spike????, and the shiffting became much better(it helped 1-2 more so than 3-4). Any help is greatly appriciated. Thanks

[Cliff8928]

If you have the Check Engine light on, sometimes the ECM will make some settings default... Like i know on the Jimmy (96, 4.3, 4L60-E) when the TPS went out and the code would set, it would default to maximum line pressure making for some very jerky shifts. It may be possible that your Lumina has a similar problem?

Cliff Scott
89 BerettaGT
89 Volvo740

[nokia]

Thanks for the reply, When i got home from work today i took care of the egr trouble code, like i thought it was cloged, and i cleared the computer, and it's still shifing rough. Is there a possibility the trans fluid pump is starting to crap out on me, or does it seem like the valve body is the only left possability?

[TheDirtyBen]

if you removed vaccuum and it got better, than i'd go with that. there is a little plastic doohicky on the vaccuum line going into the modulator (on some but not all cars). remove it and run a straight rubber vaccuum line from the steel line to the modulator. i AM assuming you have the 4T60-E tranny in this?