Newbie here! Thanks for any help in advance...about a month ago, while driving my 84 crossfire I noticed that all at once my RPMs would increase while idling. This happended in short bursts and at various times. The car usually idles around 7-8 RPM. However, it would intermittently increase anywhere from 13 to 17 RPM while sitting at a light or stop. As time passed, the frequency of it doing this has gradually increased. My gas mileage has also gradually decreased. I put some injector cleaner into the last tank of gasoline and the car ran super all week long last week. However, on Saturday while out driving it died three times with me. It didn't really do anything to give any notice, it just quietly died as if it was turned off. It was also terribly hard to restart. It acted like it was flooded, but I had to give it some accelarator to get it to start. After the third time with sitting in an intersection, I thought I had better get it back home. On the way, it did the high RPMs all the way back home. I pulled the breather and the injectors appeared to be working properly and cleanly. I am going to change the fuel filter next. Any other ideas or like experiences? Could it still be the injectors, fuel pump? I'm thinking fuel problem and the computer is telling it that it is not getting enough gas? Any help narrowing this down is much appreciated! MUCH Thanks!

 

If it were me, Start witht he basics. Check all the fuses make sure they are all good.

Does the check engine light come on when the key is turned and turn off when the car starts?

 

Thanks! I'll check fuses for sure...no engine light at all.

 

When you turn the key forward to run, before you start it, the gagues will come on along with the door ajar light, if the door is open. These will come on in the blank looking area in the center of the car next to the switches for the gagues (temp, battery, fuel info etc). Flip the key forward but dont start it. When the dash comes on, look at that blank area. Also pull the parking brake. The brake light, check engine light and door ajar light should be on.

If the other lights are on, but not the check engine light, there is a problem with the ECM. If no lights come on, you have a blown fuse.

 

Will do this evening! If ECM problem, would that mean "new computer"?

 

Maybe, but not for sure.

Do you know how to the the codes on the ECM? Where you ground out the A and B terminals on the ALDL? You can check the computer that way.

 

I would start with checking the fuses and ECM because it does not cost anything, and will verify that the computer is working properly.

I had a fried ECM in my 84 and just replaced it. Is your car an auto or manual trans? The auto trans ECMs are avail as an exchange, but the manual ones are not. They have to be repaired or you need a used one.

 

It wouldn't surprise me if you had a bunch of junk in your injectors. I recently swapped mine out and was amazed at the crud in there.

FIC (http://fuelinjectorconnection.com/shop/) is the only source for the gaskets you will need to check this out. While you're at it, you should have them re-build yours. It's something like $75 for both including the gaskets - well worth it.

 

Agreed, a very good possibility also. I have learned a few times to check the basics first. I have gone too far a few times when the problem was a very simple basic issue that I overlooked.

 

Thanks for all the good advice. My evening has quickly gone away, but I will check all of this out and post the results. Mine is an auto...so an exchange is good thing. Thanks much ffvette and MCM!

 

My 84 done the very same thing as yours is doing. Mine had a code 51 which is a faulty chip (prom) or bad ecm (computer). I replaced the chip in mine and haven't had any problems since...hope this helps also.

 

First see if you have any codes.
Second, high idle is usually related to a vac leak. Typical place for the crossfire to have a issue is the bushing on the TB shaft.

To me it does not sound like a fuel delivery problem.

Don't just start "throwing " parts at it. Diagnose and make the repair.

Typical FP reading for the crossfire is 9-13 psi at the tb's.

 

If you do have a bad chip, I have a spare.

 

Thanks to all for the help! This is a wonderful resource here.
I do have a "check engine" light that comes on when key is turned. It was difficult to see due to a smoked lens with logo over it. I have rejetted carbs on bikes before and handled the more basic repairs on my vehicles, but I've not done anything related to the computer. How hard is it? Any tips? I am reading up on the error codes now and plan to tackle it this weekend. I printed off the steps from the web on the ALDL. It looks like one counts the flashes of light to read the codes? If it is an error 51, is it hard to change the chip? Do you have to reprogram things when changing chip? Thanks MCM, I'll check this weekend and see if it is the chip. Might like to take you up on that offer. All fuses looked in order. I'll check for vac leaks too.

 

These symptoms sound similar to something that happened to my (stock) '84 a coupla years ago. New EGR valve solved it for short money...

 

Most likely not the ECU nor the eprom. But the correct indicator of the ECU and eprom is key on engine off you will see a blink of the check engine light and then full on with engine still not running. That means all is OK for ECU-eprom. If no blink then you are not running off the eprom and you are in limp mode.

 

I finally had some time to do the "paper clip-jumper-codes" diagnostics and I came up with a "15" Coolant Temp Sensor circuit & "24" VSS Vehicle Speed Sensor codes. After checking the codes, I let my baby idle for about 20 minutes. The RPMs continue to gradually and variably fluctuate between 10 & 13 RPMs.
It starts and runs good, but the sudden highs and dips with the RPMs is worrisome.
Anyone have any ideas or suggestions that I should go from here??? Needless to say, I am in unchartered waters. Thanks for any leads! Cham29

 

Check that coolant temp sensor, if bad replace it w/ a newer style. Its near the air pump, try wingling the connector to see if it acts up.

 

Is there a schrader valve somehere to measure this?