Another 1993 Skylark Hesitation on Acceleration Issue

[Sand crab]

I just purchased this nice car for $600 and it has the 3.3L and only 90,000 miles. It was owned by a little old lady who passed away and it didn't get driven much in her last years. Her nephew drove it from Bozeman to North Dakota oil fields for his work after that.
It had a bad exhaust system with holes just about everywhere and I had that done including a new cat.
It has that much discussed hesitation issue. It starts and drives perfect except during normal initial acceleration when it will bog down and stumble for about 1 second and then takes off perfectly. If you put the car in park or neutral and step on the gas then it works perfectly. I was driving on a deserted icy road and stopped the car and gave it some gas and it started out perfectly but the wheels were spinning a bit before they grabbed. One of the issues with the exhaust system was that some one had drilled holes into the old catalytic converter (clogged I guess) but when I got the new exhaust system the hesitation was worse. So, I'm thinking the new back pressure affected this issue somehow.
The nephew who is older rather than younger told me that he did the plugs and fuel filter and the oil change sticker was up to date. I popped one plug out and it looks good and the wires look good, too. I put in a new air filter and fuel filter anyway. I had the fuel filter done at a lube shop yesterday and he said they were running an injector cleaning special for February and the price was regularly $50 but now $30. He took the car for a test drive and was pretty sure that would clear it up so he says if it doesn't work then no charge. They hook a tube up to the back of the engine and some cleaner stuff goes thru. Lots of nasty smoke. So he takes it for a test drive afterward and no improvement at all. And no charge.
Now I am leaning toward the fuel pump as the culprit but what I can't figure out is why this problem only shows itself on initial acceleration. Wouldn't the car need more fuel at higher engine speeds when it is actually running perfect? It does 80 down the freeway just like it was new. And why can I rev the engine in neutral with no problems?
I assume that I have to drop the tank for this. BTW this is not a tranny issue. You can see the tach needle bob with the hesitation.

I looked at the MAF sensor and it looked clean. There is no service engine light on but I want to take it to Napa because they will read the codes for free. I'm going to check the PCV, EGR coils and whatever else I can think of. It is 10 degrees and snowing and I don't have a garage so it hampers progress. But it's going to get to about 20 below in a few days so I better get off my ass now.

Thanks Guys in advance.

 

[Sand crab]

65 views and not one reply. I guess I'm the only one at this party. Would you like another drink, Bob. Well yes I would, Bob. I'm not schizophrenic and neither am I.

My mechanic friend and I were fiddling around with the engine today under the scorching heat of February in Montana weather (2 above for the high if you must know) and he decided to just disconnect the MAF sensor that I had expertly diagnosed as clean and voila the hesitation went away. It idles crummy and surges when idling but I swear it has more power and takes right off throwing rooster tails of snow hither and fro. Tomorrow I will see if I can find a used one at the only junkyard in the county. It is supposed to warm up to a high of -7 so if I don't come back to this thread tomorrow will you please notify AF&T Salvage in Belgrade Montana that there is a frozen corpse permanently attached to the one Buick Century in their yard. I think Charlton Heston said it best.

You can take my MAF sensor away when you can pry it from my cold dead hands.

Well, it was Charlton Heston or at least someone that looked like him. I figure my hands should be thawed about the 4th of July. BOB

 

[Sand crab]

I'm still alive. It did warm up to -7 today so no parts pullin for me. It will be about 23 below but warm up to 3 above tomorrow so I need to get some swim trunks and a drink with an umbrella in it. The car idles kinda crappy with the MAP sensor disconnected but it runs like a bat out of hell. Way better than before. Maybe those Map thingys are just a way for us to spend an extra $250 bucks.
BOB

 

[Sand crab]

I went to the parts store today ready to pluck down $140 on a reman MAF sensor. First i just wanted to look at that rascal again so out come the 3 screws and it's in my hand. What I did notice this time was a bit of black fuzz but only on the intake side of the elements. This fuzz is tiny like the pubic hair on a flea and easy to miss. I went right in the store and purchased an $8 spray can of that air flow sensor cleaner and gave the old one a couple of blasts in the parking lot. It came out shiny clean and it dries super fast. I put it back in and the car starts, idles and runs perfect.

The moral of this story is to clean your MAF first when the car is running rough or whatever. Easiest 8 bucks you'll ever spend. I want to thank you all for the encouragement. I know you were with me in spirit.

 

[myold94]

good job remember the kiss principal keep it simple stupid. in other words check the easy cheap stuff first .

 

[myold94]

also the rtfm manual (read the freaken manual).