my 1989 305 tbi has been gettin progressively sluggish, car idles at like 550/600 at lights, has died a few times even, now the acceleration is draggin, shakin and just slow as slop, (no 305/tbi told ya so's, pleeze), but just wonderin if anyone else has had this problem, imagine it is dirty injectors or ignition timing gone far off. Opinion, ideas...

 

get a new engine... ditch the 5.0 tbi and go with a 5.7 tpi or something bigger that'll fit in your engine bay

 

Could just be something as simple as a worn cap/rotor, plugs, wires. Try doing a tune-up and see if she gets better. If not, check the injectors. Or if you don't want to pull them, put in a bottle of Gum-Out or some kind of injector cleaner.

-Corey

 

I'd check the compression first. If that is not constant (within 10% of each other) or is too low, prepare for a new block.

 

What would happen to a block to make the compression inconsistent? Worn cylinder walls? Newb question

 

Worn walls, piston rings not sealing, valves, head gasket.

 

If it is the heads (valves) then the block is probably not shot. Heads are definitely more desirable to replace, money-wise

 

I got the car 9/02, soon after that we did a tune up consisting of cap and rotor and new sparks gapped all to .40 instead of the .35 that is recommended on catalyst, have used FI cleaner in the past, not recently though, will try that. My guy that helps me out on the car suggests the timing is off. Since I dont know much about this process, does it just involve shifting the distributor until it matches with the timing light or is this a more compilcated process?
A little background, this doesnt have to be my daily driver, i do have a truck as well i just love driving this car, i mentioned in a pre

 

I got the car 9/02, soon after that we did a tune up consisting of cap and rotor and new sparks gapped all to .40 instead of the .35 that is recommended on catalyst, have used FI cleaner in the past, not recently though, will try that. My guy that helps me out on the car suggests the timing is off. Since I dont know much about this process, does it just involve shifting the distributor until it matches with the timing light or is this a more compilcated process?
A little background, this doesnt have to be my daily driver, i do have a truck as well i just love driving this car (especially before winter hits soon), I mentioned in a previous post that I may be getting my hands on a '97 LT1 motor and trans. If that happens, I want to keep this motor around and healthy because I may use it in the truck a little down the road. It's only got 59K on it!!

BTW i appreciate the quick and valuable input ive been getting from posting here.

 

It involves using a timing light while the timing connector is disconnected. Go to a shop and get it done unless you can borrow a timing light.

 

You make it sound sooo easy. As if you could just go pick one up at your local thrift store, install it in the parking lot, it have 0 problems and you drive away happy.

 

Does it missfire or studder as you rev it? TBI are notorious for leaky TBI gaskets. If the idle starts getting high and it's hard to start, it probably has a bad base gasket.
Any type problems like this should be looked at like this:

What "exactly"is it doing that sounds or feels wrong?
You must correctly observe and narrow the problem down, to decide what to do...
I always check for "Vacuum leaks", good spark, codes, damaged wiring(like burned on a manifold) and change the fuel filter anytime you notice a lack in performance.
**If "NO codes" it must be in the fuel or ignition systems, or vacuum leaks or mechanical like timing/chain, valve sealing etc..
To check for a plugged convertor, just unbolt it and move it out of the way and start it, if it runs MUCH better, it might be bad. Usually they will glow "Cherry red" if you run it for long while plugged, check at night.
Also check under the hood at night, with NO lights to see any cross fires or bad spark plug wires "arcing" to ground. You'll see the sparking easily..

 

well 90rocz, I appreciate that. I havent been able to get to really seeing what the problem is, i can tell you that my exhaust is now a concern also, as it has a good size rust hole right where the muffler connects. that can explain some power loss. Anyways, i know what ya mean about the fuel filter change, we did the filter change probably 5k ago and sprayed the TB with cleaner spray and the car was very responsive.
The sluggish feeling i get is a rough idle at lights and just that "duh-duh-duh" rumble feeling that the car doesnt want to go when you get moving. i understand it can be one of a thousand things, but this car is 15 years old and relatively all stock, so anything could have gotten badly out-of-whack over time. I mentioned to my guy the post that the compression could have been lost and he doesnt think that is true here due to the mileage on the car, she just turned 60k yesterday in fact.
the car rumbles and vibrates at lights, just a thought here, I changed the starter roughly 3 weeks ago and that involved having to loosen the y-pipe to get to the starter, could there maybe be a tiny leak there coupled with the s**t exhaust connection at the muffler that could be most of the problem?? that could explain that consistent rumble when sitting whether in park or stopped.
thanks in advance for your help.

 

check your plugs to see how they are... check your wires for any cracks. cap and rotor... coil... if it's none of those, then you've probably lost compression in one or more cylinders. would be easier just to do a compression check though. my car felt sluggish, and wouldnt idle right... then it got worse and worse till the point it would only turn on when i gave it gas and it would die when i let off... and when i tried to run the car, i'd slam on the gas and it would just sound louder, it wouldn't move. i then find out i lost compression in cyl 1 2 3 4 and 6 or something like that... not too coo if you ask me. car's going in for a rebuilt and is comming out with hedman headers, dual exhaust, 10:5:1 compression and probably a small bore... 355 ci or more... depending on if i can get on the machine shop's good side lol

 

wow dude, thats alot of compression to lose!! jesus, mine hasnt gotten that bad and actually a new development, my exhaust as i mentioned was rusty and what not right at the muffler, well a screwdriver and hammer fixed that for right now, no muffler is something i wanted to experience and now ill probably pickup either just a new muffler or and catback system within the next week and that will be the first real mod i'll be doing. which im excited about...
on a seperate note my plugs, wires, cap and rotor were changed right around late '02 early '03 and the plugs were gapped .040 as opposed to .035. i can assume that there is a vaccum leak somewhere due to the increasingly erratic idle, the rpm is jittery throughout the range.
: mad: