I realize this post does not involve my beloved Super Duty, but figured I’d post my experience here anyway. And if anyone else out there ever runs into a similar issue and Google’s it, hopefully the Google search engines will find my post for the benefit of the next guy. So, in a way, I’m trying to “pay it forward”.

I have a 1987 Toyota Corolla FX16 GTS hatchback. My sister purchased this car brand new, and then let me buy it from her years ago when she bought a new car. I use this car to drive to/from work – about 30 miles a day. It is one of the original “hot hatches”. 110hp 4-valve DOHC fuel injected engine in a 2200lb vehicle, easy-shifting 5-speed manual, tight chassis, 4-wheel disc brakes. This car is FUN to drive! Stops on a dime, turns on a dime, I can park this thing seemingly anywhere. The exterior is beginning to show it’s age a bit, but the interior is dang near perfect. I really do enjoy driving this (almost) 30 year old car. You just feel so connected to the road. All the while, getting about 35mpg for commuting duties. But, I digress...

A few weeks/months ago, the engine started “bucking” quite violently in 1st gear. A liitle bit at first, but it got fairly bad in the span of just a week or 2. The easiest way to describe what I was experiencing was as if I pressed the accelerator all the way to the floor, then letting it off, floor, off, floor, off, floor, off – in very quick succession. It happened mostly when it was cold, but it would do it when warm also. 1st gear, very bad. 2nd gear sometimes also. If I feathered the clutch, I could dampen the effect. But then I was wearing the clutch plates pre-maturely.

I thought it might be a bad tank of crap-a-nol (ethanol-laced) fuel. But the bucking persisted thru various tank-fulls of crap-a-nol as well as 100% petro. I inspect vacuum lines, changed spark plugs, changed air filter, changed fuel filter, ran a can of Seafoal thru it. Nothing helped at all. If anything the bucking was getting worse and worse as the day/weeks progressed.

Finally, last night, I pulled it into the garage and popped the hood, and started to have another really good look at things.

What I found was a sizeable crack in the plastic air inlet between the air filter and the intake manifold, downstream of the “MAF”. The crack was in an area of the tubing where there was an accordion-like flex piece, and it was in the bottom of one of the “accordion” folds. I put some duct tape over the crack, and took it for a drive. And the bucking is totally gone. So I guess now I’ll look for a replacement intake tube.

I wanted to post my experience because my own Google’ing turned up many, many posts where some other folks had similar bucking issues with their own cars with manual transmissions (ranging from Japanese sedans, to Mustangs, to full size trucks) and most of the replies I saw stated “this is normal”. I was totally unwilling to accept this reply. Having driven my car for years prior without any bucking, I knew for a fact that this is not normal.

Anyway, I hope this helps someone somewhere down the road.