85 FB

'85 GSL-SE 13B

This....was a subject I didn't know how to word correctly. Awhile ago, I did some medium repairs on my car. Along with a water pump and power steering pump, I also stuck on a new smog pump.

Now, today (or was it yesterday? ) is when I noticed something odd. During normal driving, anytime I come to a stop, sometimes my tachometer needle drops to the 500 mark and hesitates around there, as if the engine is sputtering. After a couple seconds of hanging out at the 500 mark, and making you think it's going to stall, the needle moves back up to the normal idle range of 700-800. It does this most of the time when I was out driving. The car has never stalled out but it makes me wonder what is going on.

Earlier today I ordered a vacuum gauge and also checked out how to read one of them. One of the listings showed "Gradual Drop of Needle at Idle" which suggested a plugged exhaust. Now, I don't have the vacuum gauge yet, it's still on order, but this of all the listings is the one that made me wonder. Now my car did get a new smog pump. Could this be the reason? I have a new catalytic w/air tube on my car, so I doubt that is plugged up. Also, when I first started the car up after installing all those new parts, I noticed some smoke coming from the exhaust hear, near the O2 sensor. At first I wondered if it was just leftover WD40 that was sprayed onto there and it was burning off. But, yesterday I recognized the same smell and wondered if it was just because it was a new smog pump and it's normal. Hey, when I stuck on my new catalytic converter, it made a bad smell but went away after the film coating on it burned off.

Would this problem be a clogged exhaust? If so, would my most likely cause be the muffler or the pre-monolith catalytics? Or, would this just coincidentally be a fuel filter, fuel pump, or TPS problem? I've already ordered a new fuel pump and filter. Any help would be great, thanks.

kmonto85

I put a race pipe on mine and that helped but I do, on occasion, have the same problem. However, my fuel pump and fuel filter are good to go and new. Therefore, I'd like to have the answer as well. I have new spark plugs and an O2 sensor as well coming in the mail. I am leaning toward a tps sensor issue.

Just subscribing to this thread...

Rx-7Doctor

iTrader: (13)

If the problem was not there before you did the recent work then you need to rechedk all of your recent work and surronding areas. Could be vacuum leak from broken vacuum line.

85 FB

No broken vacuum lines. When it comes to taking things apart on cars (now) I take extra care in making sure things are not disturbed and/or broken. I've driven the car before after finishing everything up and never encountered this problem, nor any others. Only that small wet area I mentioned before. And, that was two weeks ago. Which is why I'm asking this to see if someone has any other ideas.

Rx-7Doctor

iTrader: (13)

Usually when a sympton occurs after working on a vehicle that means that something got disturbed in the process. It has happened to me more than once.:-)

Go back and check all connections on everything just to be on the safe side. None of the parts that you have replaced would cause the synpton.

85 FB

10 to 1, nothing got disturbed. I'm 100% positive about it. But, just to make you happy, Mr. Moderator, I shall take a peek all over the engine again tomorrow when I go out to get my parts.

Scott1982

My first car (a 67 camaro convertible) would stop intermittently while driving. Once stopped while in the center of the intersection and I had to push it and ran over my own foot. Turned out some dip forgot to tighten the coil power wire - yep that would be me!

85 FB

The only things that were touched were: A/C compressor, power steering pump, smog pump, alternator, water pump, the 4 oil lines that cluster together on the side of the block near the OMP, water pump mounting block, air intake tube assembly.

........I just realized something. When I was taking care of the air filter (K&N), I cleaned it up and then recharged it with a Spectre Air Filter Recharge Kit. However, the recharge oil bottle's pump action sucked. Wouldn't spray. So I tried my best to get what I could out of it to coat the air filter. And, usually when you recharge an air filter, the oil turns that cone from grey to red. My air filter is still a bit grey. Could it be the air filter?

Rx-7Doctor

iTrader: (13)

Your reaching for straws now.

Check the air intake hose connections. Where the hose connects to the AFM, the joining point for the 2 pieces of the hose(Will be a clamp there) very common place for the tube to separate slightly and cause a leak. Also the 2 nuts that secure it to the T/Body and the small bypass air tube that comes out of the hose and goes to the plenum. My bet is there is a leak somewhere in the hose and it might be where the 2 pieces join together with the clamp.

j9fd3s

iTrader: (3)

+1 on that air hose stuff, might wanna look and see if the air filter oil gummed anything up whilte you're at it...

if thats not is, the bac valves get carboned up, and can stick...

85 FB

I'm going to take a look at the section where the two hoses connect, see how that turns out for me.

Fortunately, I hardly got any good spray onto the filter (and I let it dry before sticking it back on) for it to really get into the intake setup.