My 88 GTA started bogging about a month ago. It's intermittent. Sometimes I can drive around for 5 minutes with no problem, then it comes back. The car doesn't stall, just bogs some, and even bucks softly sometimes.

I put some isopropyl alcohol in the gas tank and I thought it fixed it, since I drove for 2 miles afterwards without any bogging. Next day the bog was back.

Today I noticed some mouse or chipmunk has built himself a big nest under the intake manifold. Don't know how long it has been there.

One of the wires to an injector has been chewed, and the plastic is off one side of it for about an inch, exposing the copper. The wire is not chewed all the way through. I'm assuming the injector is still working properly.


I looked all around the intake manifold for tubes and wires that might have been chewed, but didn't find anything else.

And what is that round valve under the intake man with a vac tube going into it? That's an EGR valve, isn't it? If the vac tube to it has been chewed would that cause bogging?

Thanks for any help !!!!

 

Well, whatever the problem is went away for at least a half hour yesterday! All I did was remove one spark plug to inspect it, and put it back in. Spark plug looked good. Gap was only 0.040. Very light ash discoloring. Almost no black carbon.

I had put some mouse traps on the front tires. No mice caught. Maybe they're gone for now.

I moved some wires around looking for any more chewed wires or tubes. Nothing. Tapped on some sensors, and tapped on the maf burnoff relay.

Started it up and watched it idle for 5 minutes. Nice and smooth. And the SES light was off, which is rare. It was bogging with and without the SES light on. The code was 36, which is maf. And the car never bogged for years with the code 36, anyway. So I don't think the maf is necessarily the problem.


Then the idle dropped a little bit, but engine still ran smoothly.

Put the hood down, backed her out of the driveway, expecting to have the usual bogging until it warmed up more. But no bog! Even at only about 100 degrees on the temp dial. Drove it around for about 15 minutes, got it all the way up to 220 when I shut it off back in the garage.

Well, maybe it's some loose connection on one of those sensors I tapped.
Or maybe some piece of junk or water in the fuel system finally moved through or dissolved or something.

 

That round thing with the vacuum tube on it under the plenum is the EGR. If everything is working and connected properly, the EGR Solenoid will control the opening and closing of the EGR depending on temperature and speed of the engine. Put a new hose on it.

 

Thanks for the reply! The hose isn't chewed, though. Looks good.

I drove it again yesterday, and the bog is back, but not as bad as it originally was. Happening at light throttle mostly.

I got another bottle of isopropyl alcohol. Maybe I'll put that in. And maybe a bottle of Techron, just in case an injector is getting dirty.

I was thinking of changing the spark plugs, but the one I pulled looked very clean, and the gap was still right. They do have at least 40,000 miles on them though!

I'd hate to keep changing things and not fix the problem.

More later.

 

rodents don't like dryer sheets or pepper spray, so you can use those to help keep them away. I use them in my garage in the winter and have had good luck. I use the dryer sheets in the car and spray around the wheels every couple weeks with some homemade pepper spray.

 

Thanks. I'm going to buy some Bouce at Walmart.

Well today was another good day for the GTA!

All I did was tap the CTS and whatever sensor was next to it, with a wrench. Well, I also made sure the MAF sensor got a burnoff cycle, by turning the key on, then off, and waiting a few seconds for the maf wire to burn itself clean. Started her up, no SES light.


Drove away, no bog! Drove her for 20 minutes, got the temp all the way up to 220 degrees, out her back in the garage.

Knock on wood. Not doing anything else to it at this point !

 

Well, the bog came bag slightly. So... I poured in my 10 ounce bottle of Techron, followed by a half gallon of gas from my plastic gas can to wash the Techron down into the tank, to see if that would clean off any junk that might be on the injectors. Now the bog is worse!! And.... it is not running as well at idle and while revving in neutral. There now is a dead spot when giving it gas an revving it in neutral, that wasn't there before. Dang! It is still drivable, but has a new dead spot while accelerating, and the soft bucking is back.

 

Have you replaced the original injectors yet?

High mileage cars they're usually wore out, low mileage garage queens they're gummed up from storage. There is almost always an improvement to be had by fresh injectors.

 

Drew, no I haven't replaced the injectors yet. There's 'only' 150,000 miles on the car now. Seems too early.

 

It's never too early with the multecs! You should also check your fuel pressure. Has the car ever had the fuel pump replaced?

 

Your description of bogging sounds like what I am having. I'm going to replace the knock sensor and see if that fixes it. It affects timing.

 

I think I have the original fuel pump in it. OK, may have to buy a fuel pressure gauge now. I haven't heard the groan from the fuel pump when the key is on, for a few months. Wonder what that means? Still starts normally though (although yesterday it started for 2 seconds then died, but started right back up).

 

I just wanted to say lol because i caught on my floodlight cam behind my house a opossom coming out from under my mazda last week. there is all kinds of twigs and sht in the engine bay now i know why.