Engine Losing Power

Need some help,
My 95 Riviera is acting like it has a rev limiter at 3500 RPM’s. When I rev it up it hits 3500 and pop’s and sputters, will not rev past (Park, or Neutral). When I put it in drive and hold my foot on the brake Idle drops to 800 RPM’s and jerks like it wants to stall. When driving there is no power, when I hit the gas there is no “get up and go”. Here is what I have done over the last 500 miles;

Fuel pump, Fuel filter, TPS sensor, MAF sensor, Plugs, wires, PCV, starter, alternator.
I just had a local shop do a full rebuild on the transmission. I would love some input. I unfortunately do not have a scan tool, and there is no SES?????
Thanks
Matt

How many miles on the car? Here's a long shot...

From GM shop manual:

"Poor Acceleration at Low Speed

If the (TC) stator is freewheeling at all times, the car tends to have poor acceleration from a standstill. At speeds above 30-35 mph, the car may act normally. For poor acceleration, you should first determine that the exhaust system is not blocked, and the transmission is in 1st gear when starting out.

If the engine freely accelerates to higher RPM in Neutral, you can assume that the engine and the exhaust system are normal. Check for poor performance in Drive and Reverse to help determine if the stator is freewheeling at all times."

i believe there is a rev limiter at ~3500 if the car is in P or N.
the popping is somewhat normal if you let off the throttle too quickly. (more noticeable if you have exhaust work done)
normal idle when warm is ~650rpm i think
the sputtering and poor acceleration could be alot of things, but if the wrong MAF is used, it's broke, or dirty then that would have the symptoms you describe.
i would double check the wires, plugs, and MAF. then check for vac leaks.
was it doing this before you had the rebuild/repairs?

I drove yesterday a total of about 100 miles to work, friends houses, home stuff like that. I was on my way home last night, about 700 feet from my house and my car just loses all power. I managed to pull it into my house, and it was too dark to start anything then. Today I went out to get food and drove it for about 10 minutes, and the same thing happened. I shut the car off for a few minutes, and then drove it home. Any ideas?

No codes, plugs/wires have very low miles on them.

How does the supercharger belt look?

Chicken wrote:

How does the supercharger belt look?

It looks fine, less than 15k miles on it. Just to clarify, the loss of power makes the car nearly undrivable, it crawls and won't rev past 2k rpm.

RhinoFLA wrote:

Chicken wrote:

How does the supercharger belt look?

It looks fine, less than 15k miles on it. Just to clarify, the loss of power makes the car nearly undrivable, it crawls and won't rev past 2k rpm.

Only thing I can think to check is the fuel filter.

Bert:tavis:

I can check it, but it has probably less than 2-3k miles on it.

RhinoFLA wrote:

I can check it, but it has probably less than 2-3k miles on it.

Probably not the fuel filter then.

Bert:tavis:

So it only happens when the engine is hot? Everything's fine before it's warmed up?

leaking antifreeze under pressure? Smell any maple syrup?

Why does the fuel filter only have 2-3 K?

Albertj

AA wrote:

So it only happens when the engine is hot? Everything's fine before it's warmed up?

Sounds like the tranny is slipping...

Well this is not the right way but you could try driving the car in a conveniant area while it has the problem and keep driving it until you get the MIL to pop up and see what the PCM says..

When the problem is a oocuring, does it also idle rough and stuff like that? Does it seem to change while it's happening or is it pretty much totally constant in severity?

It runs perfectly normal until about 10 minutes after driving it. Then it just seems like the timing goes way off because the engine starts rocking really bad, and won't rev past 2k. A couple friends told me to try the cat.. because my cat is stock so it has probably 200k+ miles on it, and a mechanic at a muffler shop about a year ago told me it was, but I didn't believe him at the time. So tomorrow, downpipe and cat delete are getting done, just because it's the easiest and quickest way at the moment. Still open to suggestions.

Otherwise it's time to get a scan tool... give us some scans and we'll give you some answers.

deekster_caddy wrote:

Otherwise it's time to get a scan tool... give us some scans and we'll give you some answers.

If this doesn't fix the problem tomorrow, i'm going to have it scanned to see what's going on before I go wasting money replacing stuff.

Actually, if you have never replaced the crank sensor - that would cause your problem. And it won't set a code. When car cools off it will run but once warm it will quit. Crank sensor wont' show up on a scanner either.



It is a $25.00 part that is a real PITA when it fails - basically it is a hall sensor and what happens is it fatigues and starts to fail warm. When it cools off the elements go back into spec. For other postings about it - failure patterns, symptoms, etc. - do a Google searh for GM Crank Sensor, Buick Crank Sensor Problem or similar - you'll find several postings about it.



If you can remove the harmonic balancer yourself - I'd just replace the #*&$(# thing, they tend to fail pretty reliably after 130,000 miles or so.



Albert j

albertj wrote:

Actually, if you have never replaced the crank sensor - that would cause your problem. And it won't set a code. When car cools off it will run but once warm it will quit. Crank sensor wont' show up on a scanner either.



It is a $25.00 part that is a real PITA when it fails - basically it is a hall sensor and what happens is it fatigues and starts to fail warm. When it cools off the elements go back into spec. For other postings about it - failure patterns, symptoms, etc. - do a Google searh for GM Crank Sensor, Buick Crank Sensor Problem or similar - you'll find several postings about it.



If you can remove the harmonic balancer yourself - I'd just replace the #*&$(# thing, they tend to fail pretty reliably after 130,000 miles or so.



Albert j

Awesome thank you, that will definitely be something to look into.

Any tips on getting to and removing it?

So it's not a common problem on s2 engines?

Hmmm... I was not talking about the cam sensor. I was talking about the crank sensor.

See

https://rivperformance.editboard.com/series-ii-engine-transmission-f4/write-up-removing-the-crank-pulley-harmonic-balancer-t1535.htm

for how to remove the harmonic balancer (use a common puller you can get at Autozone, NAPA or CarQuest)


See

http://www.misterfixit.com/crnksnsr.htm

for one example to learn the pattern of events that indicates a bum crank sensor. Do a Google search for others, there are a lot out there.

Hope this helps

Albertj

I just put in my 3" zzp downpipe, and deleted the cat. I drove it for 10 minutes, and let it idle for another 10, and nothing. Drove it home 10 minutes, and it's fine so far. Hopefully that was the culprit.

that is one of the weirdest things I've ever heard of.....