When I get about 25 mph, i let off the gas, when the car reaches about 1000 rpm it will jump to about 1300 and back and forth, all this with no pressure on the pedal. I just got the trany rebuilt, speed sensor changed and new drac and tv cable. I don't know a lot about all those parts, any suggestions.. thanks!!

 

fondled with the TPS or IAC?

also check for vacuum leaks.

 

not sure what iac is, but haven't messed with anything, can't find any vac. leaks or unplugged hoses un plugged, the tranny shop said it could be the MAF sensor, not sure how to check that though. It is very strange, it idles fine and when i brake down to a stop sign it sits just fine, just when i get to that 20 25 mph range it jumps, the speed doesnt change just the rpms like something is slipping in and out, but I have no pressure on the gas pedal???

 

My car would do the same when at or above 2000rpm. The cause was a blown fusable link at the starter. Could be that.

 

that is just right down at the starter then? I mean it sounds pretty straight forward, I will look there and see if I see them. Thanks for the help.

 

I think he means that fusible links in general may cause your troubles. Probably because of the grounding properties.

So check that your grounds are tight too, and your MAF is a good possibility too.

https://www.thirdgen.org/techbb2/sho...ght=MAF+sensor

great thread about MAF trouble shooting.

 

Not to take anything away from them, but I'm not certain I'd trust a transmission shop to diagnose a fuel control system problem. Just me, I guess.

If there is no SES lamp on the dash, it is not likely a MAF issue. Any other symptoms?

 

yes, there is ses light on the dash.....they said they thought, and your right, tranny shop may not be best place for that diagn. So with the light on, does that shed anything on the problem?

 

See what code it's throwing and go from there.

 

With the engine and ignition turned off, locate the ALDL connector under the dash, just to the right of the steering wheel in the driver's foot well area on some models, and on the left on others, depending on the make and year. There should be a small rectangular cover over the access hole in the lower dash trim, or at least was when the car was delivered.



Using a GM OBD I ECM Diagnostic Trouble Code Retrieval Tool (commonly known as a paper clip to TGO members), bend this "tool" into a ‘U' shape and insert it into the 'A' and 'B' terminals on the ALDL connector:



WITHOUT STARTING the engine, turn the ignition to the "RUN" position. Watch the Malfunction Indicator Lamp (MIL) - it will begin to flash. This is also commonly called the "Service Engine Soon" or "SES" lamp. The first code will flash three times, and will usually be a code '12'. This is encoded by one flash of the lamp, a brief pause, then two successive flashes of the lamp. Each code will repeat three times, so you should see a "Code 12" flash three times. Any other error codes will follow in numerical order, and each code should flash three times. After all codes have been displayed three times, the "Code 12" will again flash three times, then all other codes will follow as described earlier. This cycle will continue until the jumper is removed or the ignition is turned off.

After you have made a note of all error codes, turn off the ignition and remove the jumper immediately. If you forget to remove the jumper and attempt to start the engine with it in place, you could damage the ECM. For this reason you should remove it immediately.

Once you have a note of all error codes, check this file for the decoding:

GM Error Codes.pdf.

You'll need Adobe Acrobat Reader to open/print the file.

 

Awesome ,thank you for hte diagram!! I got a code 33? says the maf flow. But the question is what does that mean to me? Do I need a new MAF? Sorry but I have had this car a month now and am just figuring out the tpi system and I am no great mechanic. Can anyone shed some light??
By the way, this forum is GREAT!

 

'86,

You likely don't need a new MAF sensor. A '33' is for an indicated MAF flow that is higher than expected at a given engine RPM and throttle opening. The ECM calculates an allowable range of MAF input based on the distributor reference pulse input (engine RPM) and TPS input (throttle opening). The engine RPM signal is fairly consistent and reliable, but the TPS signal can be altered rather easily. This is another reason that it is important to set the correct throttle minimum air position and TPS voltage before anything else. It is quite possible that the TPS voltage is low, and the ECM thinks that the throttle is closed more than it is. Such a condition would normally result in a '33' error, like you have.

 

I can relate to some of what you are saying, it does make sense but it sounds like soemthing I need to bring it to a mechanic for then, not sure how to check or adjust the parts you mentioned, sounds rather complicated.............is there an easy fix?

 

https://www.thirdgen.org/newdesign/tech/tpimod2.shtml

nope you can do it yourself

 

Thanks, that info is very helpfull, I have a buddy at work who could probably help me with that, because honestly I don't know where the IAC is, lol, my birthday is thursday and hopefully the wife got my book for it! But this is very helpfull thanks, I appreciate it all!

 

one more question here, well at least one more, while taking off the air cleaner the connection between the maf and the cleaner is not a tight fit, there is nothing holding the hose into the air cleaner assembly, it is basically just sitting in there, there is a o ring there so should that connection be tight? and could that contribute to my problems?