Car jerks with acceleration, engine miss too

Good one! YES trust you guys online for accurate info to point me in good direction. You have nothing to GAIN in service work and I read a few hrs worth of your postings and advice here. Was very impressed with your knowledgeable answers to others!

Thanks much for the response. MORE INFO:
MAF was replaced Jan '06 (dealer puter diagnostics) for hard start/rough running, which solved that problem. (Installed rebuild from Checker Auto Parts.) Replaced MAF again recently under warrenty cuz I suspected MAF again when this jerking acceleration problem started. So MAF isn't the remedy here.

Nobody in LV, NV can point me to a mechanic they trust. Answer I always get is 'they're all thiefs in this town". (Living here 16 yrs, I've found it's true.) The dealers serv depts are also not to be trusted here.

Mechanic with $1500 quote based only on a test drive was a shop I never used before. In business 30 yrs in LV, maybe indicates good mechanic? Always tons of cars at his shop, never lacks for repair jobs.

He charged $82 for diagnosis cuz no work done. (I never blindlly do high cost repairs without 2nd, even 3rd opinion.) He'll credit this chg to final bill IF car is repaired there. (At drop off told FREE diagnosis. I reminded him at retrieval but had to pay it. Didn't ask for FREE in writing cuz didn't want to insult him with lack of trust at first contact. Dumb me.) Asked then if he cked spark plugs/wires etc tho car had full tune up just 5.500 miles ago. NO troubleshooting like that done, just a long test drive needed with his 'yrs of experience as mechanic' he said.( Not good enough for me! I want to KNOW it's for SURE the problem before shelling out $1500+.)

Now car's at AAMCO transmission for a 2nd opinion. AAMCO only told symptoms, NOT what other shop recommends. Picking it up later today. Hopefully puter diagnosis, not just test drive? (FREE diagnosis in writing this time!)

We've also gladly paid the $120 fee to Merc dealer for puter diagnosis (as per MAF Jan '06) in the past, and maybe the best to do for this problem now?

NO warning lights have come on even once (like serv eng soon, etc). Since car went from driving like new to jerk-jerk-jerk. I know nothing about cars & being female that's a 'juicy combo' for rip-off mechanics! Even tho always more than 1 opinion whenever high-ticket repair looms on my cars, in the end I have to TRUST someone to remedy correctly.

Besides MAF any advice how best to get an accurate diagnosis to find the problem rather than repairing using a hit and miss approach?

BTW: original fuel pump, and no eng/trans repairs or parts replaced since car new except MAF, and ALL scheduled maintenance items. I love my car and treat it well always, like Bosch Plat Spark Plugs.

Thanks for any other input you can offer! (Sorry for my long post.)

Ok, I think I can tackle the MAF cleaning. You make it sound easy enough for a novice like me. MAF was just replaced under warrenty (rebuild) less than 100 mi ago. Is cleaning needed now?

Will problem codes be stored in the motor (to maybe pinpoint 'miss' and/or jerking problems) even tho not even one warning problem dashboard light has come on since the problems surfaced? I called Auto Zone but they no longer pull codes for customers due to 'liability'. Suggested dealer puter diagnostic. Our dealer charges $120 for this, but if remedy besides tran overhaul can be found in codes, it's worth it.)

Do you suspect 'miss' is separate issue than violent jerking with acceleration (especially uphill, mostly between 25-60 mph) or do you think both problems most likely share the same cause and remedy? Could both problems be a 'dirty' MAF or a defective rebuild MAF part or some other simple common cause?

AAMCO Transmission today gave same diagnois as 1st opinion mechanic yesterday. He heard an engine miss too, but says the jerking remedy is a complete tran overhaul. (He said no codes were found in the car's puter to verify this, so basing remedy solely on test drive.) This quote is $2500, new parts to completely rebuild tran except torque converter is rebuild part. One yr warrenty parts/labor. (Car driven less than 6,000 mi/yr, doesn't seem like a good warrenty to me.) (Isn't 66,000 mi a bit soon to need a trans rebuilt with all maintenance done on time?)

Thanks so much! I do appreciate the advice!

Has the transmission filter been replaced? YES

If so when and what kind of fluid?
--new fuel filter @ 59947 mi (car now 66,000 mi)
--Fluid Type: (was special type fluid Merc needed)

Condition of the fluid? Pink, brown, burnt smell?
--trans dipstick: fluid is PINK, no burnt smell.

Would you consider this a vibration or shudder?
--shudder (jerking back and forth)

How old are the ignition wires, ignition cap and rotor?
--these 3 parts are original, never replaced.

At your recommendation, I'll request replacement of the cap, rotor, and wires while the car is at the shop Tues for a complete fuel injection service, (the last scheduled 60,000 maintenace item left to do on my '94 Merc Gr Marquis). They said they'll do a fuel pressure test too.

(BTW: cap/rotor/wires: are these transmission parts OR engine parts?)

Could you give me web links to the 2 tsb's you found about the same symptoms relating to TRANS repair? (My car at 65,900 mi may actually need a complete trans overhaul?)

Thanks! Your input is proving to be very helpful!

YOU WROTE:
They essentially entailed installed a transmission cooler, replacing the filter, flushing the lines and replacing the torque converter. Not necesarily all of them.

Are you saying maybe won't need a tran overhaul, but only the above done to fix jerking problem at acceleration per the 2 tsps you found?

(Senior on fixed income so it would be wonderful not to need trans rebuild as they advised, since it will totally tap my savings for this entire year.) 2 Light overhaul quotes were $1500 at a shop and $2500 at AAMCO. Should I spend another $120 on a dealer diagnosis or other tran shop for a 3rd opinion since other 2 places say tran needs a full 'light' rebuild?

I appreciate your help in this. Thanks!

So my car may only need a torque converter and flushed lines?
--With the current problems this car had, is it advised to also replace fuel filter (6000 mi of use on it) too?
--Do you advise a new or a rebuilt coverter?
--What's the ballpark fair price for this type repair?
--Should I now go to dealer or 3rd tran shop since 2 shops said trans needed overhaul, which per tsps you found may be overkill of repair & price?
THANKS!

Paul, I thought it would be helpful to your readers to hear the outcome of our car's problems & repairs:

The engine miss and engine shutter was remedied by replacing the original ignition wires with new ones.

The violent jerking with acceleration especially uphill was remedied with a complete cleaning of the entire fuel injection system and of the throttle body.

The transmission needed NO repair or rebuilt afterall. The first 2 shops (AMMCO being one, a local repair shop being the other) either tried to rip us off OR they didn't bother to do enough diagnostics before quoting us $2500 and $1500 respectively for a tranny rebuild as the sole remedy.

The 3rd place, Cottman Transmission, had an honest manager who is also a guru of mechanics, born and raised in Detroit, and working on cars since a small tot. He and his employee mechanics checked our car top to bottom to find the correct remedies. The repairs totalled $486, which is a far cry from a tranny rebuild at $1500-$2500.

Thanks for your advice Paul, which kept me looking for the correct answers. I hope this post will help others if their car has these same symtoms.

The repair shop quoting $1500 was malicious intent.
I can proof it. I have now called VISA to put $128 in dispute & also will contact DMV to file a complaint.

After repair shop #1 said rebuild tranny was the sole remedy on 1/11 I took car without work done. He chged $82 for FREE promised diagnostics. (Originally showed me sheet of top-bottom items to be cked. Said I'd get a copy but didn't cuz told he 'forgot' to fill it in as the diag stuff was being done.) Said he'd apply $82 as credit if I brought car back for service.

1/18 I took car back to him for a complete fuel inj system cleaning (last maint item left on 60,000 mi scheduled maint per manual. I had gut feeling inj cleaning would end jerking cuz a car I had yrs ago with same symtoms had this remedy.) $82 credit & I pd $44 bal. Invoice said only 'decarbonize engine'. He gave lame answer for no full system inj service listed. (His puter program can't discount $82 so he listed lesser service to show total chg of $44.) Oh yeah?

The following day Cottman Transmission said there had been no inj cleaning done. System was filthy. He put that in writing too, so I can pursue Visa dispute and DMV complaint with concrete proof! (End story: Shop #1 knew full inj serv/replace wires was the real remedy, and he pretended to do inj cleaning so I'd be forced to concur a tranny rebuild was needed.)

Shop #2 AMMCO: don't know if poor diagnostics or if they intended to rip me off. But, thankfully Cottman Transmission was honest and saved me a bundle!

I also had a full inj complete service at 30,000 mi along with all other scheduled maint items listed in manual, but I've always used shops with coupons to save some money with these expensive items. I did this same thing for the 60,000 mi scheduled maint.

Just 6,000 mi ago when the bulk of the 60,000 mi maint was done, why did the shop I took it to not say new ignition wires were needed? The inspection sheet showed these wires were still good. Did I pay $530 for bogus work for the items they SAID they did from the 60,000 mi scheduled maint list when maybe all they really did was install new pcv valve & new spark plugs?

I'll never know how many times over the yrs I've paid for scheuduled maint, thinking it was done properly, but instead got ripped off by 'pretended' work.

Moral of story: maint service should always be done at a reputable shop. Many 'full service' shops only do a lousy job OR pretend to do work cuz customer has no way of knowing whether or not the service they paid for is performed. I've learned my lesson and will no longer do ANY maint items at these 'coupon' auto repair places ever again!

Paul, you didn't flair me up. Just wanted to warn others of the cons of some 'coupon' auto shops!
Thanks for your concern tho!
Gail