Ok, the problem was stated once b4, but i want a new thread to try this again. Car has a hesitating chug a lugga lug type thing going on OCCASIONALLY!!! So not alwayz, not often, but every once in a while. It did it about 3 days ago when i started the car up in the morning and began driving, it would rev, then slow, rev, then slow again and again. Finally i stomped the gas pedal and the problem went away. two days passed w/o incident, then tonight i drove about 4 miles to the airport, once i got there, i let the car idle for a couple of minutes, got back in and drove it back towards campus (another 4 miles). As i crossed the highway median and then began to accelerate to get on the highway the car started doing the same thing, accelerating but then slowing a lil and accelerating again. I went ahead and changed the plugs yesterday hoping for the car to run better...it did, but apparently it's not running great still. Also, my tach is bouncing, i'm starting to suspect this is related to my problem. So here are my thoughts right now, need varification or other suggestoins.

Tach's going bad ... (now doubtful inrise of the problems)

Coil Going bad ... making the tach look jumpy and causing my hesitation.

MAF going bad ... not geting a proper A/F ratio (doubtful, kinda)

TPS going bad ... not giving the propper fuel to get it up. (LOL)

Distributor is slowly going downhill ... If time permits it might be worth it to do a rebuild i guess.

More are definately welcome...thanks in advance.

 

Alrighty...The coild going bad is DEFINITLY a possibility. I have replaced 3 on my car...all because they were defective. When they went bad, I got really bad acceleration with sputters and farts and all kinds of other things.

Your problem totally sounds like an ignition...not a fuel problem. IMHO, I think that;s where you should be focusing on.

Something else that came to mind was possibly the IAC sensor going bad. I know that when I accidently left it unplugged I had kind of a flat spot in the powerband that was kind of weird. I don't know if when something like that is bad the computer doesn't go into closed loop mode or what, but it's an idea.

 

Aftermarket tach or factory?

Have you done the wiggle test (wiggle wires while engine running) of the harness wires going to the spark coil? Notice that I didn't say the spark plug wires themselves, just the 4 harness wires.

And if you haven't rebuilt the distributor yet, find $100 and do so.

How are all the tuneup parts? How long was it since a major tuneup? Check the obvious stuff..... Oh hell why not I'll list 'em.

Check cap and rotor for carbon tracking

Read the plugs to check for signs of a problem (rich, lean, wet with fuel, etc)

Check fuel pressure

Check TPS adjustment

Use analog meter directly on TPS to ensure "smooth swing" (resistance setting) during full range of throttle operation; don't hook analog meter to computer or you'll fry something

Ensure that the timing mark for #1 cyl TDC on the balancer is accurate, and that the balancer hasn't slipped

Check timing after making sure of balancer mark being correct

Check PCV valve operation

Check all spark plug wires with a multimeter, stock wires are about 15,000 ohms foot, aftermarket varies

Check for air leaks in the intake ducting

Check compression in cylinders

Check alternator output, should read 13.8 volts with voltmeter at the battery when engine running

Check battery output, should be 12 volts with ignition off (if battery older than 5 years, replace it, no questions- if you bought a decent battery like an AC/Delco, Sears, or Interstate (no exceptions to these manufactures!! These three only!) you might be able to push 6 years.)

Perform wiggle test on all harness wires between coil and distributor and computer

Check exhaust system for leaks between (A) heads and manifold, (B) manifold outputs and y-pipe inlets, (C) cat convertor and y-pipe, (D) cat convertor and intermediate pipe, (E) any rot in pipes after cat

If automatic, possibly the TCC is sticking

Check vacuum-operated EGR, could be sticking in open position. EGR activates when all of the following conditions are met: (A) engine temp is warm/hot, (B) high road speed, (C) light throttle. If EGR sticks open, it might not deactivate when you slow down. Try putting a golf tee into the vac line that goes into the EGR and go for a drive- and remember the golf tee is wood so don't let it catch fire.

Just a few off the top of my head at 2:00am after a few cold ones

 

TPS problems on my TBI car caused similar issues, so don't rule it out.

MAF I'd be kinda doubtful of, but those same symptoms existed on my friend's TPI car when his MAF was shot, so, once agian, hard to rule out.. not to mention he replaced the MAF, and the problem didn't go away.. thanks to the new MAF being shot right out of the box..

It's just one of those problems that's going to be annoying to diagnose without computer feedback.. so many things can cause it, but without a code, scan tool, or buttload of spare known-good parts, it's hard to figure out who dunnit.

 

Tom, thanks for the extinsive list of things to check out....was kinda hopin you'd reply to this. I had pulled the plugs the other day, the old ones checked ok, the new ones are in now....gonna pull the cap/rotor assembly, it definatley needs to be checked out....also gonna pull the distributor when i get a chance to see about it. I'm kinda thinking that it may be an issue w/ the TPS, but don't konw. The MAf was replaced a year ago at a shop i had dealt with many times (very reputable, and won't screw ya) they used a remanned MAF sensor for $$ sake, also replaced the Pickup coil on hte distributor, some vaccuum hoses and wires going to the coil itself. I think i might have some problemswith those wires to the coil, not the plug wires however , although i think i'll check resistance on those, there 8.mm Accel products, but tehre a couple years old. Heck, the cap rotor combo's the same age, so i guess it's a going to be leaving me soon for a replacement one...i'll just go down your list tom and try everything i can, hopefully i'll huhnt this down before i'm forced to find a 500 dollar solution...ya get the idea.

 

Well luckily a lot of my list can be done for free, as long as you have the tools. Keep us posted!

 

Tom, definately have any tool i could need, or have access to it. (working as an aircraft mechanic, theres a plethra of tools laying around the hanger.) And...when in gods name did u move to Cali? Running away from that cold weather are you?

 

Location: Central NJ, USA - but now, LA, CA!

WHOA! When did this happen? Where in So Cal are ya stayin man? You should check out the So Cal boards!

 

Whoops; I thought I changed that back. No, I was in LA last week for a business conference. It really sucked to come back to NJ.

See this message for a bit more info on my trip: https://www.thirdgen.org/techbb2/sho...18#post1559137

 

great list by Tom but don't miss your ECM !!
cause the same thing happened to me last year.
I did like Tom's list - put in everything new- still same probs.
New ECM and everything was fine

good luck - Horst