DPG Omaha

As the subject says, this problem is very stange, but I'll try to explain the best I can.
Basically, the problem normally occurs when I'm in D or OD. It happens most when I'm going about 60 mph, and want to accelerate to 70 mph or so in OD. I push the gas pedal about halfway (not enough for a downshift), the car will begin to accelerate and then all of the sudden, I lose power: almost like I'm coasting with my foot off of the gas. If I keep my the pedal in the halfway position for about 5 seconds , the SES light comes on. When I let my foot of of the pedal, the SES light will turn off after about 5 seconds. Also, when I let my foot off of the gas for the 'condition' to stop, I feel a good thud in the drivetrain, kind of like the engine reconnecting with the wheels... if that makes sense.

I got the code from the SES, its 33: "MAF Sensor, Excessive Airlow Indicated. I replaced the MAF with one that I got off of a friend. I'm not sure how good this MAF is though, it was descreened and ported. No difference.

A couple other notes...
From a stand still, the car accelerates to 90 mph normally (floored), with little or almost no hint of a problem.

Shifting from 2nd to D is also kind of different. Before, the car shifted pretty smoothly, from 1st, 2nd, D, without too much change in RPM's under normal acceleration. Now when it goes from 1st to 2nd smootly @ around 2500 rpm, and then when it shifts to D, the revs go to about 1200 - 1500 RPM's , which feels very 'jerky'.
I'm at a loss for what this could possibly be.

Thanks in advance.

350TPI

Did you replace the MAF relay?These are sometimes the culprit and are way cheaper to replace.

DPG Omaha

Not yet. Do you think that can cause all of the above?

350TPI

If the car is still throwing the MAF trouble code then it has to be the MAF relay.There are 2 i think.One is the burnoff and the other is for the MAF itself.I would replace these(they are cheap)and see how it runs.

DPG Omaha

Sounds good. I got a relay on the way and will be put in tomorrow. I hope it works!

Tru2Chevy

MAF trouble aside, it sound like there is something going on with that tranny. For it to suddenly starting acting odd and shifting weird in only one gear usually won't be fixed by something electrical. In 89 the 700R4 was still completely hydrolically controlled, with the exception of the lockup. I would check the MAF stuff, then unplug the lockup controller and see how the car responds. That is the four prong plug on the drivers side of the tranny.

- Justin

Rice Killer87

i agree with him,sounds like the torque convertor lockup is screwin up.

DPG Omaha

Well, I replaced the MAF power relay and all the problems vanished. How a MAF power relay could cause all of the symptoms I had really boggles me. The tranny and torque converter lock up issue is gone.

Is the torque converter lock up controlled somehow by the readings from the MAF?

While I was driving with the problem, my car would do 2100 or more rpm @ 70 mph. Normally I should get less than 2000. If I pushed the gas pedal just slightly, I could get the normal revs and TC lock up. Push it a bit more - failure... no power, hold the pedal, get the SES code. Let off pedal, SES goes away. Weird!!

I hope no damage was done to my TC while driving it like this.

Thanks!