Shadetree 101

I know this is a long post but I wanted to try to spell everything out. Alot of post i'm reading the replies are asking for more info.

The car sat for about 2 years needing a clutch. Got clutch fixed and drove it from Louisiana to ST.Louis, Mo and back. Total 1500 miles or so. Three months after the trip I bought gas and got water. Mechanic pumped water out, changed fuel filter, added ALOT of fuel additive, refilled the tank with good gas and she ran great for about 2 weeks then this started. No he did not drop the tank.

SYMPTOMS: tach needle jumps around so much it's an orange blurr or drops completely to zero for a few secs then jumps back up while the engine is running normal. However, sometimes the tach gets jumpy and so does the engine too, like it hesitates, loses power then gains power all of a sudden so the car drives all jerky. When the engine starts jerking it will disengage the cruise control. This can happen at any speed, even highway speeds but most of the time when it hesitates, it usually does it under acceleration from a stop. Sometimes it hesitates so much it feels like its gonna stall, and sometimes it does stall. When i first start it in the morning, night or whatever, 99% of the time it'll start fine, but once i drive it, it might start acting up 200 feet away from my house or 200 miles away, just completely random. Most of the time it's around 20 miles or so. Sometimes when it acts up the car stinks like a mixture of burnt and unburnt fuel. Mechanic claims it's the additive I smell but I've burnt about 4 full tanks of gas through it since then. I have really gotten on it before, tach hitting about 7k rpms, and just tried to blow it out cause it acted like it was trying to flood out. That works sometimes and everything goes back to normal for a while. Most of the time it doesn't though. Any help would be so appreciated. If I had hair I would've pull it out about now.

nus_dogg

Have you check your positive and negative battery post? Reason I said that is because my positive post had some gray stuff built up on the inside of the connector where it wraps around the battery post. You won't see it unless you disconnect the battery cable from the battery. Mine started acting up where if i'm doing 70mph then all of the sudden the speedometer would drop to 40mph and back to 70mph just a matter of sec. Then my car would not get power at all if I turn it off and try to start it back up again. Power with all the dash light comes on for a good 2 secs or so but slowly fades out then car won't start. I had to sit there for a good 2 mins or so for power to all of the sudden come back and thats when I start the car up fast in case power fades out again.

I kind of know my electrical, so knowing that only a battery can provide power when the engine's not running, there's gotta be something between the battery post; either the neg or pos post. I did a voltage drop between the post and connector on the pos post and there was quite of a number there. Also, when there was no power with KOEO(Key On Engine Off), I lightly tapped each battery post and when I tapped the pos post with my rachet and BAM! Light suddenly comes back on. So I knew right then that it's a battery corrosion issue. That can cause your RPM to jump around, but could be alot of things. Just sharing what I went through for mine.

I'm not sure what will cause your engine to hesitate either. I'd make sure all engine grounds are tight and corrosion free,

Shadetree 101

Thanks for the reply. Checked that stuff and all was good. Wife took the car to work and now the rpm's won't go over 3500. Acts like it's governed. Could it be the catalytic converter after having the water in the gas issue?

Shadetree 101

***UPDATE***
I found the problem with the jumping. The drive belt had fraid and hit the wires going to the ckp,tdc sensor. I spliced them back together and it is driveable again but the tach started jumping again.

97ludedude

I have seen the ignition control module (ignitor) in the dist cause this issue with the tach. Just a thought.

Shadetree 101

Thanks ludedude for the possible cause. My son got under the car and was looking at the splices and told me some of the white wire was not caught in the connector. He respliced it and the car runs like new again. Strange how something so simple can cause that.