Hey guys,
I was meeting up with some friends before we went up to a cruise-in when my car all of a sudden started to just miss and jump and whatnot. I as going about 50mph and it was doing it without me even acccelerating any more than I was. I would left off and it would be fine for a little bit and start doing it again. I left my friends and went back home...on my way, it got to a point where I was only able to go 5 mph and the car still felt like it was about to stall...at this point I was getting backfiring out of the exhaust.

Before I went to meet up with the friends I had to get fuel, I put about 13 gallons in, so she was about empty. Within a half hour it started doing this. I just now went out to syphon some gas to put in a clear jar to see if there was water in the fuel....while doing this I noticed my gas cap was barely on. Not even a full turn or anything. Could this gas cap not being on make the car do this....and if not, what do you think could cause this.

I just recently in new plugs, wires, coil, thermostat, cleaned air filter, and some other tune up things and I drove the car the day before and that week and nothing ever happend until this day after fueling up.

What do you guys think?

 

Sounds like fuel filter or fuel pump that's what i would check first.

 

I just had a new fuel pump put in it a year ago and havent drove it much sense then and do you think the filter could clog and unclog while I was driving....

I will be driving and it will just all a sudden start misfireing and I wont even move my foot and she will clear up...its wierd.

 

It doesn't take much to plug up a Chevy fuel filter especially if its a fram the filter on those are half the size of the ac delco filter on the inside they look the same on the outside i really hate fram filters.

 

Hi, i have been having problems with mine somewhat simalar, but im not sure if your car is fuel injected but if it is then I had a problem on my 88, and it was the temp switch which is behing your thermo on the intake. My mechanic friend told me to unplug the temp switch and see if it still acted up. That fixed it he said that was causing the car to run very rich and choke out. I replaced it and it fixed it. Hope it might help, its easy to determine whether that is it and not labor extensive.

 

You mentioned new plugs wires etc. Double check firing order, and make sure a plug wire didn't pop off a plug or the dist, and check wires for shorts (check continuity on each wire). I've had a wire come off a plug just enough to get backfiring, and I've also more than once gotten bad wires in a brans new box of wires - including Taylor Made wires I had a bad one of those. I dont think the wire folks ever test their wires, just cut to length and shove in the box.

 

92RSMoneyPit - I know, I have changed mine atleast 3 times. I just don't see how it could unplug itself while I am driving and keep plug and unplugging.

camarodubs - Hey, my car is indeed fuelinjected with a TBI. I am not exactly sure where you are talking about with this temp switch. Is there any way you can post a pic or maybe I can find it in my Haynes book.

camaronewbie - I know fire order is good, I been driving it for atleast a couple months since I have changed plug wires. I do still need to check if any boots came off the plugs...it was too hot to check that when this all happend but I did check on the cap.


So I am guessing noone thinks this could be from bad fuel or the gas cap.?

 

92RSMoneyPit - I think the first thing I will do is change that fuel filter.... I do believe there is a fram in there right now. Where do I buy the ACDelco.....can you only get that from the dealer or can you get it from a auto place or walmart like you can oil filter?

 

I went out and checked the plugs at the cylinder as camaronewbie mentioned I do think that number 5 cyclinder was loosed. She pulled off pretty easy as none of the others pulled. I wouldn't of doubted it being loosed becuase with the heddman headers, plugs are a bitch to push on. I think number 5 is one of the worst. So, it took me about 15 minutes to finally get it to SNAP on and I hope that solves the problem. If the problem still persists, I will get back on here and let you guys know.

 

Just went out and drove it for 20 min and at like 15 min. she started to do it again.

 

Does it run good the first 15-20minutes ?

if it starts to run bad when hot it could be the ignition module in the distributor or the pickup in the distributor, those are not a fan of heat...

the module in the distributor often fail when overheated or old.. So I would check it out..


Will the RPM start to go up and down trying to maintain a steady idle and then lean out and start to go good again ? or will it keep going bad all the time ?

 

It does run good until she warms up. I am not sure about the tach, I didnt really pay attention. I been reserching on here about the magnetic pickup and it seems a couple people had my problem and this fixed it. It is only like a $20 part so I might as well throw it on there and see what happens.

 

I have a 1½ year old MSD 8366 Dizzy thats broken again, was broken when I bought it (bad ignition module) and now yesterday it gave up again... im so sad about it...
ignition modules in sweden costs shitload of money, and I think that a MSD product should hold longer then 1½ years (only drives during summer in sweden, oct-april its in hibernation in a warm garage during the swedish winter..)

Mine starts to missfire for some secc (3-4seconds) RPM goes up and down and the RPM gauge needle is jumping around due the bad signal from the dizzy...

 

I order mine through local auto parts store i haven't found a store besides the dealership that has them in stock i have a new one in my rear glove box all the time just in case.
I had a fram chevy fuel filter come apart on the inside once when you take yours off shake it if it rattles you found the problem.

 

I will have to try that. I hate replacing it though, gas just comes running out like crazy. I never knew a way to keep it from doing that.

 

So, I tried to replace that pickup coil and couldnt figure out how to dissasmeble to get it off....I saw no c clip holding it on...so I bought a new MSD dizzy. I just got done putting it in....forgot to mark sparkplug to fixed point to keep timing right. The car is running, but def. at retart and once I get a timing light and special wrench I will take her out and see if that was the problem. I sure hope it was.