Need some help? I have a 90 camaro 3.1 with the following replaced in the last month. Fuel pump & meter assembly, fuel filter distributor cap, rotor, plugs, wires, ignition coil, PVC, TPS, IAC, manifold air temp (MAT) and new exhaust after the cat. I also replaced two injectors that had bad resistance with two "non reconditioned" from another Third Gen'ers 3.1. I have also bought and not received as of today a set of reconditioned fuel injectors that I will install. I also purchased an Actron 9150 to read the codes and real time data as well as three 90 camaro service manuals.

As far as the code 44, I plan to replace the O2 sensor this weekend.

I am more concerned about the code 35. I just installed a new IAC, TPS and Temp manifold temp switch, and I did not have to adjust the pintle on the IAC. I actually opened the top cover of the plenum where the IAC is inserted to verify the pintle was not extended to far to be damaged during installation.

The car starts and runs after I replaced the two fuel injectors. The car actually performs (quick response for pedal) better than it has for 10 years; I have only driven the car 100 miles since all the parts were installed.

After driving abound 15 miles, the Check Engine light (SES) came on. The car still ran well, but I did notice the rpms seemed to be driving the car at 20-25 mph without me pressing on the gas. Before I shut the car off, the car idled about 1150 - 1200 rpm. When I started the car, I do not have the check engine light.

I have triple checked if there is a vacuum problem. I sprayed starting fluid at all vacuum lines and near the intake manifold. Before I replaced the IAC unit, I disconnected it and started the car. The car held a slightly rough idle at 700 rpm. I am thinking if there was a vacuum issue, the rpm would be higher.

I used my scanner to deleted the 35 and 44 codes, and to be extra sure, I removed the battery cable simply because that's what I am use to doing. When I read the codes from the ECM without starting the car after reconnecting the battery (and clearing the data on the scanner), I am still getting a 35 and 44 with the car not running.

Can anyone tell me if the 35 and 44 codes cannot be reset the way I am doing it? I read something about soft codes, but I do not know what they really mean. My check engine light is off, I disconnected the battery, and reconnect after waiting 30 seconds, put the key in but do not start the car and I still have the codes.

I read that the code 35 is set after a period of time (I think 45 seconds) comparing the command rpm versus the actual rpm. I am puzzled as to why without starting the car I still have the code 35 after I disconnected the battery.

I did notice that when the car is cold (it is 20 degrees in MD), the IAC does seem to control the rpm at the commanded rpm after about 30 seconds. If the car is at idle, the car runs RICH. When I return from a 10 mile trip, the car no longer holds the command signal of 850 rpm, but is around 1200 rpm.

When I accelerate, the car is running LEAN.

Any thing you can suggest would be great!

 

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Ok, disconnecting both battery cables for 10 minutes removed the codes....thanks.

Now I no longer have codes at idle. I do have carbon blowing out of the tail pipe?

Can any comment as what causes carbon spots coming out the tail pipe?

 

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Ok, so I no longer have carbon coming out of the tail pipe because I took it out for a spin at 75mph for an hour. Then, I replaced the O2 sensor. The car IAC seems to be working as when I start the car cold, the rpm's go to 1500 and then slowly go down to about 800.

What I am noticing now is that the car wants to idle at 1300 (in gear or neutral) after I come off a high speed run, and I have to rev the engine "once" to get the idle to drop down to 800.

Besides a mechanical issue, does any one know what might be causing this?

Car seems to start, accelerate and idle ok as long as I step on the pedal after a long run.

 

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WD-40 did help. TPS was showing 2% before wash, and 1 % after wash. I believe the real problem was the way I tightened the throttle linkage screws (2). After the WD 40 bath, I loosened and re tightened both screws, and I could tell they moved to a different more aligned position.

Thanks for your help!