Okay, last year I finally finished my 87 Camaro restoration project. The car has a 305 TPI out of an 88 Iroc (if the previous owner gave me the proper year information) and an automatic trans.

Here is what I have done to it:
1. Autolite 26 spark plugs
2. MSD 8.5mm Wires
3. MSD Blaster coil
4. MSD cap and rotor
5. New throttle cable and kick down cable (I did adjust it)
6. All new gaskets from the intake base plate up
7. Set base timing to 6 degree advance
8. TPS and coil tested good

The problems:
1. When I start the car, the idle is around 600-800 RPM. After about 5 minutes the idle kicks up to around 1000-1200 RPM.

2. After the car is warm, it hesitates on acceleration from a stop, but picks up great when acceleration from 25 MPH.

3. The car sounds good at idle and at WOT, but under normal driving it sounds like it is consistently missing (does not seem to miss if given throttle in park).

4. The motor stalled while driving at 55 and also during acceleration when I got to about 30. No stumbling before hand, just plain died. Started right back up both times.

5. After hard acceleration the car lost most of its power and turned the check engine light on with codes 42, 34, and 33. The car was acting like the timing was majorly retarded, which I believe was because the EST was disabled. I unplugged the MAF connector and reconnected it and the problem went away.

The car is getting 12-15 MPG, which is why I am almost certain that it is missing and that its not just the way the exhaust sounds. The potential issues that I have seen are melted wire tubing near the headers, but the wires seem to be okay.

My main concern is that one of the wires is the knock sensor wire. I am thinking the problem may be EGR or distributor related. I have been going around and around for a little while trying to chase this down and am running out of ideas. Thanks in advance for any advice

 

I did some more testing and driving and found that the two codes that continually come back are 34 (MAF) and 43 (Electronic Spark Control fault). When code 34 is set, the car stumbles and either comes back or dies but does not have any loss of power. Code 43 seems to always be set at or near WOT and results in major loss of power and slow pickup of RPM, generally until the car is turned off and started again. Any ideas?

 

I have all the symptoms you have except the check engine light. I have an 87 305tpi also, my buddy has a 1994 Cadillac 350TPI i'm thinking of building to LT4 specs and putting in. These 305 motors are garbage i hate it your not alone.

 

Yeah, I've been tossing around the idea of putting a 383 in it instead of sinking money into a 305 with barely 200 HP. However, my checkbook is against me...

 

Lets see. when it sets the MAF code, unplug it and see how it runs.

under load how bad does the car ping? make sure the knock sensor is connected. and make sure someone did not switch it between the fan switch like someone goofed up on my 87'

is the TPS set to .54v?

what injectors are you running?

 

TPI is TPI....just because it's on top of a 305 does not make the 305 garbage. Some have just been treated much better than others. Saying an engine is garbage just because yours is is not right. My old modded 305 TPI handed it to 350's and I never had many problems with it.

And to the OP, 2 things come to mind with your symptoms. First is the MAF itself. If you have any freinds with a good one, swap it out and see if it fixes it. If not and you have to try a new one, do not get the autozone crap. Get an AC delco. They are not cheap but they have a heat sink inside them to dissipate heat where as the cheap parts store ones do not so they will last a few months at best. And I agree with the guy above me...when the problem happens, try unplugging the MAF and see if it gets better.

The second thing is your fuel pressure regulator. It could cause the car to get terrible gas mileage and stumbling since it will be cramming much more fuel into the engine if it's bad. Do you notice any black smoke when driving?

 

I'll try unplugging the MAF the next time it starts running bad and see what happens. The TPS is at .54v closed and 4.7ish at WOT. I have stock injectors, which I believe are the 19lb on a 305. The fans kick on at the correct time, so I believe the plugs are connected to the proper sensors. Knock sensor is plugged in and I recently put a new pigtail on it because the old one was slightly melted, but it made no difference.

The MAF is a bosh that has been on the car for 4 years, but only seen about 3,000 miles. I'll plug in a fuel pressure gauge and see what the pressure is looking like as soon as I can. Thanks for the replies!

 

Code 34 is often a symptom of leaking fuel injectors that can be flooding the motor. With the fuel pressure guage connected shut the car off while in park. If your fuel pressure drops to zero right away the injectors are leaking.

However, I think you may also have an ignition problem. The shutting off during driving shoulds like a bad ignition module or pickup coil in under the cap.

 

I finally had some time to get the car out and do some testing. I tested the fuel pressure and it seemed good. I say seemed because the gauge I had to use wasn't in the best shape.

I started checking the condition of all the vacuum lines and found that the one coming from the reservoir was in pretty rough shape. While trying to replace it, the male end on the reservoir decided to break. I ordered a new one so we will see if that changes anything.

While I was test driving it last night and today, I repeatedly lost power for a second followed by the check engine light with code 34 and 43 and loss of power, which I believe is the car going into limp home mode.

I've tried all the testing I can think of and the TPS, coil, plugs, wires, timing, and MAF read as okay. I did find that the MAF connector has a broken clip. I'll be putting a new pigtail in soon. I am also planning to replace the knock sensor due to a chip in the connector.

I am leaning toward throwing an ignition control module at it since it seems to be one of my best bets at this point. Any input on that? Thanks again.

 

I installed a new knock sensor and the car runs much better. It has not set any codes since I put the sensor in. The car still has no power off the line, but I am beginning to think this may be transmission related.

I've been checking over the vacuum lines and found one line coming off the charcoal canister that I am not sure about. I included a picture of the line. It is currently connected to a plastic line that runs to the bottom of the throttle body (second picture). The plastic line has vacuum when the car is running. Is this the proper connection for an 86 or 87 (not really sure since the motor was changed by previous owner) 305 TPI?

 

I would like to follow up on this since I see a lot of these threads that never seem to have a conclusion. I recently removed the distributor cap while searching for something that looked like it may be the problem.

I found that the wires that go from the ICM to the pick up coil were brittle and loose. I also tested my coil once more and found that it was bad. I put a reman distributor and a new coil in it two days ago.

I haven't had a single issue with it in 70+ miles. No more check engine light, no loss of power or stuttering, and it has way more power than it did before. I have not had the chance to check on the gas mileage, but I am fairly certain that it is no longer getting 12 MPG. I think it safe to say the problem is solved. Thanks for all the replies and ideas!

 

Nice man! Problems like this are a pain in the A**, but boy does it make ya feel good when you find it! TPI is great when it runs. Only problem is that because of how arcaic the computers are, they really only give you an idea of what a potential problem MAY be when they throw a check engine light. But glad to hear she's running good now.