This started happening all of a sudden. When I first give it gas it surges then bogs down, and when I let off it surges. Any other time it bogs, like mid gas and WOT. Still pulls hard most of the time when I'm above 3 grand.

91 3.1 Firebird Recent mechanic work. CAI and Seafoam

I have since changed the fuel filter, plugs, wires, ignition coil, and visually inspected the vaccuum hoses.

 

IMO, possibly TPS, or alternator going out.

I would also look into the injectors getting PROFESSIONAL cleaned.

Other then that, sounds like you started with the very commen things to inspect during troubles.

 

Check the ignition - cap/rotor and module

 

is it hard to start? I had a coil go bad and it made it very hard to start. Then when I was below about 3500rpm the engine bogged down and then surged when the coil finally fired. Above 3500 it was ok, but still not what it should be.

To check the TPS, get a Digital miltimeter and set it to the lowest voltage setting. Shove the leads into the top and middle wires where they go into the connector, and turn the key to ON. Don't start the car, just turn it on. Go to the front of the engine and the voltage should be between 0.51 and 0.6 volts. If this is cool then open the throttle slowly and make sure that the reading goes up stedaly to about 4 volts. if this is ok, then your TPS isn't the problem. if either one of these checks if wrong, then you need a new TPS. If the Idle voltage is wrong, and your car has an adjustable TPS then you can just loosen the torx screws holding it on and twist it until the reading it right, then tighten the screws back down. Be careful though, these things tend to break off. I think all of the 2.8's had adjustable TPS, but the 3.1's were non-adjustable.

Search for and do the TomP tune up too, that'll help a lot. Good Luck

 

Can you throw a fuel pressure gauge on it? I had similar symptoms when my second pump died. Low rpm= car didn't want to move, higher rpm= car moved okay. I had to two-foot-it at brake lights to keep the rev's up... good thing it was late at night with almost no traffic or I never would've made it home.

 

Don't have one handy, maybe this weekend. The only thing is it idles fine, and when I'm not in gear it seems to run allright. You can tell there's something wrong but it revs fine with no real noticable hesitation.

 

Doward, hit the nail right on the head, you need cap rotor, wires and coil. Also does your tach twich when going a constant speed. This means you have a coil pick up problem. Basic requires a distrutor rebuilt. I did it. Fixed all my problems like these. Also be sure to disconnect the brown wire/black connector when setting the timing.

 

Woops I see that you have change the coil and wires already. I would try the pick up coil change and a new module

 

it is a 91 3.1 and my TPS settings were .65 up to 4.35 is this bad? Will it hurt anything? It's been like this for 182,000 miles.

Distributor rebuild is in progress. Thanks guys

 

Sounds good, remember anything under 1 (yours .65) the computer auto zeros meaning closed butterfly.

 

DaGoat, do you have a manual or auto? Have you ever had to do any major tranny work in 182,000?

 

 

Auto
Since I've had the car, tranny fluid and filter have been changed twice, and now that you mention it's, probably bout time to do that again. Knock on wood, not a single problem, and still shifts like a charm. The car was previously very well taken care of though.

 

One more question. Anyone who has remote located their Ignition coil, have you had any problems with feedback? If so what did you do to correct it? Mine makes a whirring noise consistent with the rpm's.

 

No I made a braket and put mine on the fender.

 

KED85 mouted his kinda on the upper firewall, he post pics of it all the time.

I am thinking about doing similer this summer to mine. Get it away from that damn EGR valve.

 

Yeah that's where mine is also. Hopefully he'll see this and respond.

 

I put mine on to the shock tower straight out from the A/C fan motor, clears the hood fine, way cooler over there then right on top of the exhaust manifolds.

 

Any troubles with dist/coil wire length?

 

I do/do not have radio interference.
I wired radio incorrectly.
Previous owner coucldn't keep hands off the radio harness, so I got screwed.
Radio works, drives to short in LA to enjoy radio anymore, the coil is great idea.
Do the coil remote mount.
Plan it well, then drill. Make sure all wires stretch there first.
That's the reason for my location, wires stretch there safely.

 

Might as well throw my coil picture up... as long as your distributor-to-coil wire is short "within reason" (ex: not 6 feet long), and not routed so as to cause spark leak, you should be fine.

The coil I run is the MSD Blaster SS.