It's a '95 Z28. If I barely step on the gas to keep it at any speed it "bucks" and calms down only when I let it coast. When I accelerate at highway speeds, it sometimes backfires, after the "bucking" stops. It will accelerate, eventually. The air filter is brand new. What is going on?

 

Any codes?

 

Sorry, I don't have a scanner.

 

Check for things like:
-dirty MAF sensor
-torn air inlet elbow
-burned or cracked plug wires
-worn plugs
-dirty fuel filter
-low fuel pressure
-weak coil
-faulty IC Module
-faulty Optispark
-etc.......

 

I think he just covered it all... If those all check out then you might want to check the O2s and TPS. Just a thought

 

If it only happens after the car has warmed up, it is most liekyl a bad O2

 

Low fuel pressure would be the first thing i checked (since that is what happened to me)

 

Possible burnt plug wire.

 

Thanks for all the help. Guess I have some pokin' around to do. It is back-firing more the last few days. It has a K&N cold air system and I changed the filter but that did not help. I can't remember when the fuel filter was changed. Must be at least 7 or 8 years ago. How hard is that to change? The plug wires all look good but the plugs are also about 7 or 8 years old.

It bucks real back when I back up out of my driveway when the steering wheel is turned. Time to get some dirty hands.

 

Fuel filter is pretty easy. Just make sure you release all of the pressure from the line, or you'll be getting a gas shower (a mistake I won't make again). There is a good write up somewhere on here.

 

IS the check engine light on?

Go buy a fuel pressure test gage.

It sound like you have not been maintaining your car. How many miles are on it?

If this was my car i would do a full tune up (opti, wires, plugs, O2's and so on)

 

i would check the coil..

 

I admit, I have not taken as good of care of it as I used to. Before getting married. I had an "exhaust leak" that I eventually found a few weeks ago. One of the hoses was rotted out. I found another one yesterday that is rotted out. Both on the bottom of the hoses, making it harder to see. I wiggled a few hoses and one fell apart. Replaced that and no more exhaust fumes in the car. The one I found yesterday is on the lower passenger side of the throttle body (a vacuum inlet) that leads to a silver "box" over the passenger side valve cover. The 3 inch hose is also rotted out. I have it duct taped for now until I get the $12 hose tomorrow. It didn't buck quite as much today but my tape job is not covering the whole connection. It also took a few tries to start the car after I reconnected the hose.

No telling how long it has been like that so should I be worried about anything being sucked into the TB?

 

it may not make a difference, but was the backfire from the engine or did it happen at the exhaust?

 

From the exhaust.