Ladies and Gentlemen,
This has been a long road. I have solved many trouble codes to include MAF, EST, TPS, ECM, Burnoff Module, etc. Bottom line, car runs well, good mileage, and ok acceleration while pushing the throttle slowly. If I punch it, nothing happens. I am beginning to think that there may be a transmission issue. Any guidance would be great.
Mark

 

Explain what you mean by "nothing happens". It revs, it don't rev, it doesn't make any noise, it doesn't speed up, it slows down?????

 

while you do need to answer arbees question, ill toss a clogged cat into the mix. thats what mine was.

 

Thanks for the response, when I hit WOT, the engine does not change speed or RPMs. I am thinking the TV cable may be the issue. I will check and adjust if possible. I have not pulled the Cat, but I will since you have reminded me. More to follow. I have been chasing this issue for 10 months.

 

While readjusting the TV cable is never a bad thing, I don't think the trans has anything to do with your issue. Others well versed in engine management will be your go to.

 

Thanks, my scan tool only reads the codes for OBD1, I am going to build a cable so I can use winALDL and hopefully get more clarity.

 

Try pulling your O2 sensor and see if that allows the engine to rev better. There should be a few psi coming out the hole but most should be heading out back.

 

I will try that, the engine revs just fine when I move the throttle body, so I am going to pull my throttle body and clean it, and replace the TPS and IAC, I have the parts coming and they were not expensive from Rockauto. The issue only happens when I drive, stationary the engine runs well

 

Hello MarkB85vette,

When my previous DD the car sat for about a month and I came back to get it. It would start right up and idle fine, when you gave it gas it would just gurgle and rumble. With the hood open I was in the car and I started it and I saw something change under the hood. There was a "Sniffer hole" in the exhaust system and it had a black rubber cap on it. Whenever I hit the gas the vacuum cap turned into a balloon.

I will almost bet you have an exhaust blockage of some sort.

On the subject of throttle bodies be careful how you clean it. GM used some kind of light rubber surface material to enhance the sealing of the blades in the TB. It can be removed by over aggressive cleaning. Don't use any steel wool or anything on the throttle body. I soaked mine and cleaned the functional parts. Be sure the vacuum lines are there and everything seals up nicely.

How about the Mass Air Flow sensor on your Corvette? They measure the volume of air being pulled into the combustion process. The MAF sensor (If you have one) uses two separate relays to operate it. One supplies Power to the unit and the second controls a function called the "Burn Off". The reason for the burn off is that it removes the buildup that occurs as air is pulled over the tiny wires (1/10 of a human hair) for hours and hours. When the Burn Off function is activated it heats the wires up in the sensor until they are glowing orange and then shuts off automatically. Frequently when people have MAF issues they replace the MAF but not the 2 very important relays.

How does your Engine act when you first start it up and then when it switches to "Closed Loop"?

 

Thanks for the response. My MAF tests good based on the FSM trouble codes. The Burn off module did not hold the correct voltage for the correct amount of time and I replaced it last month. I replaced the O2 sensor over the weekend. It was giving me a code, forget which one but it is now gone. I have not pulled the cat yet. I am little nervous on the cat because the bolts look a little shaky, don't want them to break. I pulled the TB today, I am going to by pass the coolant running through it since the climate her in Corpus Christi is so warm. I notice there was a lot of sooty carbon like build up in the plenum. Seems like I should pull that and clean it out. I have all of the gaskets. Also while the TB is out I am going to put in a 180°thermostat.

Funny thing is the car will spin the tires off the line but after that when you hit WOT or literally seems to go into a limp mode. I am hoping the new TPS and IAC will at least help. The old ones look as old as the car.

If I pull the Cat and it is clogged, can I punch it out or does it have to be replaced? The smog pump line on the side of it is welded on. More to follow. I am determined to figure this puzzle out. Thanks again for the help.

 

One more thing, where is the relay that supplies power to the MAF?