I honesty don't know wtf is going on with my car.

The engine is an 2.8l from my 89 RS now in my 90 RS.

I'll start it up. It'll have a tough time keeping the idle and will die out. I do this about 3 times and then it'll keep the idle but still run rough.

Drop it into drive, press the gas, and it'll go but there's hesitation up until I believe 20-30mph's. After that it doesn't chug along but when I slow down to stop the idle gets rough again.

While driving on the highway, I'll let off the gas and I'll hear it backfiring a little bit, which is annoying and a bit embarrassing.

I've replaced the Dist. cap, Plugs and Wires. Fuel pump is idk about 5 months old probably. Changed the Fuel Filter before that too. I did the timing to 10* like the sticker on the bottom of the hood said. Still have the same problems.

As of now I don't have the Fuel Regulator line going to the Air Pump, it's blocked off. Will be replacing the line tomorrow.

My dad is suggesting to replace the injectors since they have about 180k+ miles on them. Before I go about doing that is there anything else I should check?

I will also clear the codes, drive around and then see if I get anything.
Help meh because right now I'm just losing patience with this

 

Here's pics of the spark plugs - Bosch 4x Platinums

#1 -
#2 -
#3 -
#4 -
#6 -

Didnt take a pic of #5, battery died. Basically looked like the rest of them.
Figured I'd take pics of these, don't know if it'll help or not.

I didn't clear the codes and go driving today, but here's what I did get - 13, 23, 33. One thing I did notice when looking in the Haynes manual is that all them had defective ECM.

 

13. Oxygen sensor signal stays lean during warm engine cruise
23. Low temperature at manifold air temperature sensor OR Throttle position sensor error
33. High voltage (low vacuum) at mass air flow sensor (or MAP sensor)

#1 get rid of those plugs they are worthless and are so easy to foul,99 cent autolights/champions work just fine
#2 i would verify the readings on the map/tps and temp sensor
one of those is deff bad if not anyof those i would look at the o2 sensor next

 

Alright. I'll change the plugs.

The o2 sensor is new. Bout less than a month maybe. When I installed the Pacesetter headers the o2 sensor was farther back than the original and the connector (from the harness wire) ripped off. I cut off that wire from my 89 rs and soldered it to the wire where it had ripped off which made the wire longer and able to reach the o2 sensor.

How would I go about verifying the readings on the map/tps? Should I just go out and buy a new one?
Hate to sound like an *** but uh, what temp sensor you talking about?

 

u need a multimeter to verify the readings on the map/and tps
sorry i meant the air temp sensor

 

i heard bosh spark plugs are no good for these cars (weak spark or something). Maybe try some ACDelco's R43TSK that's what i got.

 

yup acdelco r43ts r42ts or r43tsk's are pretty much the best for these things

 

double check timing...could be a tooth off!!!

 

yeah bosh plugs are lame. auto lite are my fav just because they are the cheapest and they alway fire. i do like acdelco but i only use them when its running reall good and no tune up is needed.

 

There is a good chance it is just the plugs. They ran HORRIBLE in my 2.8

 

I never had any problems with these plugs. Who knows, maybe the luck ran out. Bought some AC Delco's today. It's the r43 somethings. Will post up my results later tonight.

 

Well, I'll make this short. I switched the plugs last night. Gapped to .45. Seems to run a little bit better than before. Redid the timing with the light gun to 10* (it was off a little bit). Runs slightly better. I do still get that little hesitation and backfiring.

I'm going to replace the Rotor today.

I picked up the Throttle Position Sensor aswell for the hell of it since it was mentioned in one of my previous error codes. Problem is IDK where the hell it's located. The Haynes book says at the end of the Throttle Body Shaft and shows an upclose pic of just the sensor. That really doesn't help me. Does anyone have a pic showing more than just the sensor itself? ( i feel like an *** for even asking that heh).

After this is done I will clear the codes and test drive around the block couple times and see what codes, if any, come up.

 

Question, 2.8 & 3.1 Throttle Position Sensors. Are they different styles or the same?

 

Well if anyone cares the problem has been fixed.

Turns out it was the Air Temp Sensor that was bad and giving the computer a hotter temp than what it really was.