I have an 89 Firebird with the 2.8 and it starts right up but has no low end power.

It has a shudder in the engine that seems to happen at random but frequently and when the rpm's are low as in taking off after having slowed down, it has almost no power and knocks and shakes untill rpms increase and after a certain point it runs smoothly in the upper rpm ranges untill you slow down again. You have to make it downshift to stop knocking and dragging during acceleration. Or else just take off REALLY slow to keep the load off the engine.

It really jerks you around when it does this.

I just put a code scanner on it and it pulled the following codes:

12 Normal

13 O2 Sensor Oxygen

21 TPS

22 TPS or Fuel Cutoff Relay Circuit open or shorted to ground

23 TPS or MAT or Mixture Control Solenoid (M/C) open or short

34 MAF or MAP

44 Lean exhaust indication - Oxygen Sensor voltage stays low


I am going through the information on these systems now.

Any ideas whats going on?

I can think of everything from a clogged cat to multiple system failure. (run it off a cliff)

What does it sound like to you?

Thanks,

KJay

 

well with all the codes to the TPS. Good bet its bad(check the connector first). I would also bet your running lean(the stuttering no power ect). either o2 is bad or there is a short in the mixture system/control. I would have the MAF checked... thats a $$$ sensor.

 

I replaced the MAF with a rebuilt one I bought on EBay (cheap).

It made no change but I will see if NAPA can check them. I still have the original one I took off.

Seems everything points to a new:

TPS
Oxygen Sensor
MAP
Manifold Temperature Switch (pressure)

And maybe the MAF


Where is the MAP?

 

This kinda happend to me, one or more of your pistons might be mising. check your plugs and change your plug wires. also switch to midgrade fuel

 

MAF sensors were used on 85-89 2.8's, MAP sensors (speed density) are on 90-92 3.1's. It's just two different ways of measuring air flow. MAF sensors measure it directly, by measuring the vibration of an orange frequency film inside the sensor. MAP sensors measure it indirectly, by measuring engine sensor output, and cross referencing those numbers against a table that's stored inside the computer chip. Both systems have their positive aspects and negative aspects...

With all those codes, I'd say to clear the computer first. Some codes could be old ones. The way I like to do it is by disconnecting the negative cable from the battery for a little bit. In theory, you only need to unhook it for a few seconds; I leave it off for a minute or five. Then go for a ride so the computer re-learns the engine (and finds the error codes)... I usually drive a half hour away at highway speeds, then I'm forced to drive a half hour back at the same speeds. Cruising around town will take longer for the computer to relearn the car (and the engine will run rough for a while until it relearns it).

 

Ok, do this for us.

#1. Disconnect battery cable (negative) for 10 minutes.
2. Drive around.
3. Read codes writing down IN ORDER as they come.
Then post to us IN ORDER which they are.

Thanks.

 

Okay, I disconnected the negative terminal and took it for a 20 minute drive.

Interesting. Now I have:

12 Normal

23 TPS or MAT or Mixture Control Solenoid (M/C) open or short


(according to the Actron manual)

 

Do you have a multimeter? If so, TOMP will tell you the values your TPS SHOULD be reading.

Make sure those are it, if not, move on to the Mat, then blah blah blah.

 

I dont have a multimeter yet, so I ordered a new TPS from NAPA today. It should be in tomorrow. Seems like a good place to start.

I will get a multimeter too while I'm at it. Never used one before.