mclenty0

I have a 1986 305 v8 firebird and whenever I accelerate the car falls on its face, it loses all power and jerks me around, it seems to drive fine when I slowly put on the gas for the most part or when I slam the pedal to the floor. I can't figure out what the problem is, any help?

someone972

iTrader: (2)

What style of intake does this have on it? TBI/TPI/Carb?

mclenty0

carburetor

zraffz

If it never used to do this and just started recently, I'd start by checking for major vacuum leaks. Otherwise, Internet diagnosis is the carb.

mclenty0

it has done it since I bought it, I bought the car as a project car to fix up I was just hoping someone else on here has had the same problem and fixed it and could tell me what the problem is, as of right now there is no exhaust pipes. It is coming straight out the headers I don't know if that could be part of it?

zraffz

If I understand you correctly, when you smash the pedal to the floor it doesn't bog but at the same time if you ease into the throttle it doesn't bog? So when exactly is it bogging?

Does it have a hard start or run rough at idle?

mclenty0

If I smashed it to the floor it doesn't bog but when I ease into it it does bog, I'm thinking it's a fuel pump buy not sure

sofakingdom

iTrader: (1)

Definitely a fuel delivery issue of some sort.

Did changing the fuel filter make any difference? What did it look like?

Probably not the fuel pump, but it can't be ruled out completely.

No the exhaust is probably not a factor in this particular matter. Best to get it resolved though.

mclenty0

Well the car has almost all symptoms of a bad fuel pump which is what is leading me to belive it is the fuel pump that is screwed, and I think now would be the time to get it changed because there isn't exhaust pipes in the way. I wanted to get this problem situated before I out the pipes on it

bop11

Sounds more like clogged jets. Smashing the throttle pumps in raw gas from the accelerator pump, which means you do have fuel in the bowl. Slowly pressing the accelerator, requires a transfer from idle jets to power jets system which probably are plugged and thus starving out the engine.

zraffz

I'd also assume fuel system but the fuel pump wouldn't be my first choice.
I'd look over the carb. Check the float levels first. When you take the screw out, no fuel should spill out but if you gently rock the car with your knee fuel should splash out.

I'd also verify fuel pressure. You could be right that it is suckling the floats dry because the pump can't keep up, but I doubt thay.

Fanatic1074

Does it seem to bog down at any certain RPM? Bad ICM can cause issues just like this too.

mclenty0

No it's just when I ease onto it and even when I smash it the floor it will will back fire and not give full power

sofakingdom

iTrader: (1)

How'd that fuel filter work out for you?

larsulrik

My 92 305 tbi has been doing something similar for a couple of weeks. I took off slowly from a stop sign and it puffed and sputtered for like 10 seconds until I finally got power back. It does it every morning on the way to work from any stop for about 15 minutes and then it's fine. It does it in the afternoon on the way home for the same 15 minutes but not as bad. Sometimes it has a hard time starting and other times no problems at all. Sometimes out of nowhere when I restart a warm engine it idles from almost stalling erratically up to 1500 and back for a minute and then evens out. If I floor it at highway speeds while things are acting up it feels like it's struggling but if I let off the gas just a bit it actually accelerates a little better. I'm getting no SES codes when it's happening. It's been purring like a kitten for 225,000 miles and now suddenly I feel like I own a junker. I'm doing a full tuneup this weekend with genuine AC parts for once. Plugs, cap, rotor, o2, oil change, fuel filter, new vacuum hoses and setting my timing back to 0 from 4. I'll let you know how it goes. I'm really hoping someone will chime in and say it's definitely not my fuel pump. I really don't have time to change that. Hoping it's just the fuel filter since I don't remember the last time I changed it.

Aaron Colegrove

I've had a very similar issue, 1989 Camaro 305 TBI.
Ik i have a fuel leak, and I have an occasional issue where it sometimes will run perfectly, and other times i'll press on the gas, the RPM's won't go over 2500 and it just has no power what so ever, but when I let off the gas it lunges forward.
I've already ordered the replacement fuel line, next week I'll be be ordering a new fuel pump, and I already bought a new fuel filter.
I have on order a throttle body rebuild kit, and a few cooling components.

I'm thinking my issue is somewhere between the fuel leak and the fuel pump. And even if it wasn't the fuel pump, since I'm dropping the tank i'm upgrading anyways.

larsulrik

Mine did exactly the same thing for the last 2 weeks so I did a full tuneup this weekend. The center springy pin inside the distributor cap was gone leaving only the little spring to send spark to all the plugs so I was sure that was it and then my fuel pump went out before I finished the tuneup! I'm not sure which one was the problem; probably both.

mclenty0

Okay so I put full exhaust system on and now see that it is backfiring from the carb, and when I get on it more then 10% it bogs and backfires even when I try Rev it in neutral it will backfire and bog but once I try punch it a couple times it will rev all the way to red line as if nothing were wrong, I've read up up online and I'm thinking it could be the accelerator pump, or its not squirting enough fuel, I checked and I'm pretty sure the fuel filter is supposed to be right by the carb on the fuel line but there isn't one. Idk if that could any other problems but gunking up the carb there is a little filter inside the carb where the fuel line goes to but idk what else the problem could be