kretos

hi guys

well its been getting worse, when i'm out a drive the cars will start to stumble when i give it gas, by stumble i mena it will start to jerk alot. it seems to happen more at night when i have lights and such on, so i was wondering could low voltage cause this to happen, and does anyone have other ideas?

camaro350man

check your plug wires in the dark and see if they are grounding out anywhere. Move thme around if you have to. Hope it helps

kretos

that was first on my list, i'm also getting a bouncing tach, so i'm starting ot think my wires might be fubar'd

85berlinetta2.8

clean your iac, change your plugs, and check your tps voltage, clean your cap and rotor.
those are about the cheapest easiest things to do to help the problem.
scan codes.

kretos

cap and rotor have under 15000km tps im in the process, iac is clean, plugs are under 20000km, and i'm getting a code 15 and 34, the cts is getting replaced this weekend, i know the maf can cause problems but it can't be this bad

85berlinetta2.8

change your plugs anyway, it only cost 6$ ansd takes 10 minutes

Dizturbed One

i have the same exact problem.

the car started jumping and surging whenever I drive it more than ten miles or so.

Sometimes it'll go about 40 miles before it happens, but then it does it so bad that I start worrying about it and have to let it sit for a few hours before I can drive it again. It does it REALLY bad if I try to step on it.

Before it does that it runs great though.

It starts right up, sounds great. I just did an oil change and the motor ran even better. It doesn't throw any codes. Changed the fuel filter...

The tach jumps around pretty wierd. It'll be fine sometimes, but then it'll get wierd for awhile and act really twitchy and jumpy. When the car starts surging back and forth under acceleration it starts jumping really wierd though.

I bought plugs, wires, rotor, and cap, hoping it's something ignition wise...

Then I'm going to drive it down to get a coil just for peace of mind (and I like doing associated things all at once)

I'm going to do the plugs, wires, rotor, and cap right now. I'll get back to you later on if it helps.

Dizturbed One

well, i haven't pulled the plugs yet, but I was out there and I pulled the cap and rotor and slapped the new ones on... I will be VERY suprised if it isn't the cap and rotor... There was heavy white buildup on the cap terminals, and the end of the rotor was colored brown and burnt looking... not to mention there was brown spatter all over the entire inside of the cap.

its all the stock stuff still... even has GM plug wires on it... THIS CAR IS 13 YEARS OLD!!! SOME PEOPLE AMAZE ME

I've had the car over a month and I'm AMAZED at how well the car has been running with this cap and rotor in it...

When I'm done eating I'll put the new plugs in and give it a spin.

82-T/A [Work]

I've never had this problem with an F-body, but in other cars with this same motor, I've found that it's usually related to:

A) a bad or failing MAP sensor.

B) a bad or failing MAF sensor.


I forget which you guys have (with the 3.1s), I believe you have MAF sensors? The MESH sensor that sits behind the air box but in front of the throttle body...

This is either dirty or needs replacing. This is the same symptoms that all cars like this have.

If you don't have a MAF system, then you likely have a different system which uses a mix between an IAT (Incoming Air Temperature) and a MAP sensor (Manifold Absolute/Air Pressure)

This is often attributed to a failed MAP sensor.

It HAS to be either one of these...

A failing spark plug, or wires that are arcing would cause hesitation, poor idle, and sputtering, but not jerking.


Hope that helps.

Dizturbed One

i've only driven it a couple miles, but i just got it all back together, new plugs, wires, cap & rotor.

it hasn't even hinted towards it, and the tach hasn't quivered a bit.

i let the car warm up completely before I took it out, which usually causes the problem to act up almost immediately, but it didn't this time.

I'm convinced it was the cap and rotor... They were COMPLETELY trashed. White buildup all over the place (literally caked on about an 1/8 of an inch on the cap terminals)

The plugs had some white buildup too, but not much, and they looked otherwise clean, and gapped correctly... I threw my new ones in anyways.


ANYWAYS

NOW my car wants to die when I drop it from the middle of the RPM range though... If I'm cruising along at 2500 to 3000, then I push the clutch in, it drops to below 500 for a sec and wants to die until I tap the gas. Then it sits back up around 900 like normal.

But if I downshift all the way through the gears and come to a stop, it only does it about half the time.

???

camaro_junkie

kretos, check the connectors going into the coil. I broke the retaining clips off of both connectors and when I replaced the coil, the terminals on the new coil were looser, allowing the connectors to slip out. Caused jumping and especially an erratic tach.

kretos

new plug wires solved my stumbling problem.

thanks guys