'95 surges on acceleration AFTER warmup

[dosMarkos8to's]

My 95 has been surging- if it had a carb I'd say it felt like the float was set too low. Problem doesn't appear until after driving for 10-15 miles, runs fine up to that point. Tach shows fluctuations of up to 500 rpm up or down
when its doing it. Will stop surging if given more accelerator. Smooths out at higher(60mph) speeds. Starts it @ low(20mph) speed so not trans lock out problem. Good wires and plugs,fuel filter, not hearing vacuum leaks.
Any suggestions on what to check out?
TMM

 

[NoLimit95]

Do you have stock exhaust and have you ever changed the 02 sensors. MAF ever been cleaned? How many miles are on the car? There could be 20 different things causing the car to do this.

 

[dosMarkos8to's]

Stock exhaust,no sensor changes,no MAF clean(didn't think it was cleanable?)143K.
Today I drove to town on a low tank of gas (low fuel warning on) and she ran fine, no
surging for more time than usual, put in 6-7 gals. fuel and immediately the surging started as I left the gas station. Thanks for responding NoLimit95. TMM

 

[GMAN]

Sounds like a vacuum leak.

 

[dosMarkos8to's]

The way this surge is inconsistent would support a vacuum leak. Are there any diagrams of the vacuum system to help make it easier to check out all lines?
There is no apparent vacuum hiss and it seems to be temperature related, are there any components of the vacuum system that would be affected by temperature, that could swell and open a leak when the heat up?Thanks. TMM

 

[NoLimit95]

What I would suggest is to get you one of those code readers, disconnect the battery for a few minutes to clear all codes and then drive it until it starts doing it again. Connect code reader / flasher and see what shows up.

EGR or related could be acting up on you. Whatever it is, is heat related from the sounds of it. I would clean the MAF for sure. Change air filter while you're in there, unless you already have. 4 bolts holds the box together and the bottom left is hell to get to but you'll manage. Use CRC MAF cleaner (silver can). It is sold at Advance, Auto Zone, and many other parts chains. Seeing and us knowing what your 3 digit codes are would help out a lot.

They do sell vacuum manuals on ebay for your car. Go into the for sale section also and put up a "WTB" post for a vacuum manual. Maybe someone will have one to sell.

 

[NoLimit95]

http://www.ebay.com/sch/i.html?_pppn=v3&_kw=Mark&_kw=VIII&_kw=vacuum&_kw=manual

 

[GMAN]

The simple and easiest way to detect a vacuum leak is to spray some starter fluid all around the intake and the rubber hoses. The leak will reveal itself by sucking up the fluid and idling momentarily. If you're lucky it'll be just a vacuum hose or something like that. If it sucks around the intake, then off with the intake.

 

[dosMarkos8to's]

Great help/advice. Will do and get back. Thanks guys. TMM

 

[dosMarkos8to's]

I'm getting a brake light warning after applying the brakes, stays on for 10-20 secs.,
brakes work fine. Also wondering about vacuum to the trans and how that could effect shifting. If there is a vac connect to the trans,what part could go bad and cause erratic shifting. This only happens after warm up/driving for 15-20 mins. All symptoms disappear if I open the throttle wide,goes like the bat out of hell you'd expect it to be.
TMM

 

[Right on the Mark]

I'm getting a brake light warning after applying the brakes, stays on for 10-20 secs.,
brakes work fine. Also wondering about vacuum to the trans and how that could effect shifting. If there is a vac connect to the trans,what part could go bad and cause erratic shifting. This only happens after warm up/driving for 15-20 mins. All symptoms disappear if I open the throttle wide,goes like the bat out of hell you'd expect it to be.
TMM

No vacuum to trans.

 

[GMAN]

I'm getting a brake light warning after applying the brakes, stays on for 10-20 secs.,
brakes work fine. Also wondering about vacuum to the trans and how that could effect shifting. If there is a vac connect to the trans,what part could go bad and cause erratic shifting. This only happens after warm up/driving for 15-20 mins. All symptoms disappear if I open the throttle wide,goes like the bat out of hell you'd expect it to be.
TMM

You are low on brake fluid.

 

[NoLimit95]

You are low on brake fluid.

For sure on that one!

Now it sounds like it might be the TPS but again, read some flashes with a tester.

 

[mistermaclincoln]

When was the last time you had your fuel filter changed?