well i searched through the archives and found alot on this topic. and although none of them really sounded like the problem i am having i started trouble shooting. well it dissappeared for about two weeks and now its back and really don't know what to do next.

THE PROBLEM: i don't know if its really considered a hesitation, but when i try to accelerate, not so much at WOT but sometimes, the trottle response is horrible and i can feel the car jump in acceleration from more power to less power. and it seems like it gets more common as the car warms up.

for an overview of my ignition, i have and MSD GM blaster coil, MSD superconducter 8.5mm wires, Bosh platinum +4 plugs, and I also just replace my fuel filter.

i also checked for codes to see if i have a bead sensor somewhere and i have no codes. so i am confused now at what can be causing this, since my ignition is almost entirely MSD and brand new.

two weeks ago i ran the engine off of five plugs, going one cylinder at a time to see if maybe a cylinder isn't fireing, but the idle was much more rough w/o a plug than it has been trough acceleration. then ironically after checking for codes the problem dissappeared. oh, and i also had to re-tighten my exhause manifold becuase two of the bolts came loose and it was leaking.

i know this is a lot of info, but i am trying to figure out what the problem may be....any insight would be great!! i have never checked my timing, i don't know how that affects a car, and i don't know what to check next....thanks for any help, Rob

1990 Firebird 3.1
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ASP underdrive pulleys
MSD GM blaster coil
MSD Superconducter 8.5mm wires
Home made C.A.I.
Hooker 2.5" exhaust (in my garage )


[This message has been edited by SAEspinz80 (edited June 20, 2001).]

 

I would say : check timing and O2 sensor.

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www.marion-becker-nidda.de
91 Firebird 3.1
Modsynomax ultra flow stainless steel -americanracing rims (ar26) rear 15x8 255/60
front 15x7 235/60
www.members.aol.com/tramphorst/pontiacpics

 

if i think were thinking of the same think, does it feel like bucking? Like the car will go forward, slow, forward, slow? If so..my car does the same thing and im coming up on a rebuild...

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1989 Firebird
2.8 v6, t5 swapped in

Ram Hi-po clutch, Cold Air, 1.6 rockers,Lakewood LCA's, Lakewood Lift bars, Wonder Bar, 3" y-pipe, Random Tech Cat, 3" I-pipe, Flowmasters, MSd 6a, MSD Coil (Fireball in future) Accel 8.8 wires, MSD Ignition Module, Auto Meter Gauges (Water, Clock (needed one) Fuel Pressure, and 5" monster tach)TB Bypass, 4th Gen Seats

Coming for my v6:
Panhard Bar, 4thgen front seats, Nitrous, Line Lock, and Ram Air 2 hood

"I'd rather run last in a full out race, than to not have run at all"

 

actually it may be the bosch plugs...I have heard by many a people the GM V6's hate em. Other wise it may be timing... Did you disconnect the EST when you set it last. I know mine just ran into timing probs out of the blue. reset and everything is fine now...It would "buck" like grame said surge forward then fall on its face then go again..was a real pain in th a$$. Was kinda like when you first learn to drive a stick and you keep dropping the clutch..rocking the car... not as severe though..but thats the closest thing...

 

i dunno if its the plungs cause about two weeks ago when i tightened the manifold i had rapid fires in that were overgapped to .055, so i gapped them down to stick .045...and that didn't help the problem so i put the platinums back in because when i ran them last year the car was great. but "bucking" is a good word, altough its nothing like the bucking when first learning to drive stick. its much more subtle...but you can feel the car accelerate, ease, accelerate, ease...ya know. i think i may buy a timing light if they aren't too expensive. i don't think (and hope) its not a rebuild. the car has 91,000 miles on it, and was only driven 2,000 miles between 1995 and 1998. it was adult owned and i am only the third owner and has run like a charm engine wise.

what are signs of a rebuld anyway?? since i don't really know....any other input on a solution would be great, i keep racking my brains and appreciate the help.

 

I have this same hesitation, but its not all the time right...? Mine takes a spell where it won't do it for a week then at stop signs when I am pulling away, it will hesitate then you punch it and it will boog then take back off.

Mine is an EGR Vacum leak, or atleast that is what a mechanic told me... Just a suggestion...


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1987 Firebird
2.8L Auto
T-Tops
New Paint last Fall
No mods yet...

 

you can get a timing light for 20-30 bucks... I highly recomend it.

 

Sounds like a timing chain mission.
These engines need that one part, in good shape.
Your timing light will tell ya easy.
IF ya get the light, shine it on the balancer.
If the mark jumps, you found your problem.
It's due for replacement.
Not to hard.
Not to expensive.
Call 800-831-0884
About $50 for Fel Pro & Speed Pro parts. Delivered.


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Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA

 

I've dealbt with this my egr valve was carboned up ,creating a vacuum leak, replace and while your at it adjust the throttl position senser. disconnect it and put three jumper wires in, then turn the key on[be careful not to ground the wires] then take a volt meter and put it in terminal a & b the top two you should have .54 volts give or take .075.. my 2.8 liter mpi likes it at .580 volts I get a much better response also make sure you have more than 4 volts at WOT

 

Man, my Blazer used to do the EXACT thing it sounds like. It would go fine for a while, and then run really crappy, SOMETIMES (rarely) even backfire. I tried all the EGR stuff (valve, solenoid), Coil, Cap, Rotor, Plugs, Wires, TPS, 02 Sensor....and I can't even remember what else. I finally sold the thing in one o it's "good" spells.