Mechanics

OLDS 98 - HESITATION UNDER HEAVY ACCELATION

1993 Oldsmobile Other

Make: Oldsmobile
Model: 98 Regency
1993
213555
3.8L - fuel injected

Ok. Here it goes.
Acceleration is fine when car is cold, but after warming up under moderate acceleration car stumbles and surges then under hard acceleration condition improves slightly, but more noticable when it stumbles. Another symptom is when attempting to shift out of overdrive the car jerks a few times before in gets out of OD. BUT if I accelerate quickly the transition is smooth out of OD. This just strated to happen recently and I initially thought it was ba gas, but the situation has not improved after a few tankfulls of gas. I don't want to start throwing ignition parts at the car until I have a grasp of what may be the culprit. I'm thinking a coil pack, but what perplexes me is that when cold the accelation is great, no hesitation. It's not until it warms up that the problems starts. Thanks for the help guys!
Avatar
Microracer
October 31, 2007.



Start up the car and disconnect the MAF sensor. Does it run better then? If so you have found the problem, get back with results.

Blackop555
Oct 31, 2007.
Well, I tried disconnecting the sensor before starting and it wouldn't start at all. I have not tried starting then disconnecting the sensor, but I'm guessing I'll meet with similar results. I'll post later after the test.

Ok, as I suspected. As soon as I discinnected the MAF the engine died. I did notice that the MAF is a reman'ed unit and not the original.

Tiny
Microracer
Nov 1, 2007.
Well, I replaced the MAF and the problem still exists. Can someone please give additional feedback, thanks!

Tiny
Microracer
Dec 18, 2007.
Hows the tranny fluid looking and smelling does it smell burn or have a brownish tint if so you should have the tranny serviced, also drain the fluid and check for metal shavings, if you have shavings then you should examine the tranny gears for wearing.

Blackop555
Dec 18, 2007.
Recently changed out fluid and looks fine. Looking at other boards, I suspect a Air Intake Tempetaure sensor. Ever heard of these symptome in relation to that sensor?

I'm also wondering if the lack of power is messing up the kickdown out of overdrive. As I mentioned earlier this thing is great until it warms up, then the problems start to manifest themselves. I guess fluid temp of the trans could be causing the OD issues, but the stumbling, I'm thinking Air/Fuel mix. Thoughts?

Tiny
Microracer
Dec 18, 2007.
Im thinking its a tranny issue all the way because of the OD kickdown, when fluid heats up it expands. Sometimes cars trannys dont work properly untill the car heats up! Check the tranny fluid coolers if equiped to see if they are cooling properly.

THe IAT sensor isnt a common problem, and isnt really key. It can make the condition worse but its not really a big part of the fuel to air ratio system.

Is it possible you can get it scanned for trouble codes?

Blackop555
Dec 19, 2007.
The check engine soon light has not come on at all, will there be any trouble codes in the computer? Never would guess tranny on this one. Thanks for the tip. I think the cooler is in the radiator, how can I check?

Thanks.

Tiny
Microracer
Dec 19, 2007.
Basically just check for leaks on the line, and full fluid that is not brown or having a burnt hose, the cooling lines are usually mounted near the radiator.

The IAT is hardly ever the problem, and does not cause much of a problem.

Smell your exhaust is it rotten egg/sulferic smell? Post back.

Blackop555
Dec 19, 2007.
Went to my local Advance Auto and described the problem and he suggested a new set of wires. BAM! No hesitation and the shifting problem went away too. Smooth as silk getting out of OD. Man cars these days. Give me a Big Block Chevy and a 4bbl carb! Thanks for the help and keep up the good work!

Tiny
Microracer
Jan 8, 2008.