92ES300 Misfire Troubles

:banghead: I have a 1992 Lexus ES300 (glorified Camry) which I bought used with 127k miles in 2000. It now has 249k. It's the first car I've ever bought and I'm pretty sentimental about it (especially since I've spent allot of time keeping her running.) It does not presently have any A/C at the moment but this isn't my pressing problem, and it only needs a condenser to be back up and running. Here are my apparent problems.

Initially, I was experiencing a small slip in power at acceleration (like a miss.) Soon after this happened the car began to roughly idle when coming to, or at a stop.
I also experienced an exhaust/gas smell with smoke visible from the muffler. The car also sounded loud.

From here I took the car into a shop that has been good to me in the past. All said and done the distributor, distributor rotor, spark plugs, ignition wire set, ECM, upper and lower valve cover gaskets, and a cold start injector were replaced.

The car still was a bit louder than it should have been but ran fairly well for a while; nevertheless, the problem was back within the week and has the same difficulty getting up to speed (meaning 40mph) with rough idling and visible gassy smelling smoke.

I noticed there was a small leak at the EGR pipe/exhaust manifold connection so I refit the pipe and gasket so there was no leak, but the noise was still present. I took the car in to have the front muffler connection checked along with the catalytic. There was a small crack in the front mufflers flex bend which they fixed but the catalytic is said to be in good shape. I’m going to take the car into another shop I know and have them take a look at the timing belt and EGR Pipe connection into the back manifold, but ANY thoughts would greatly be appreciated. Thanks!

A loose worn timing belt and tensioner can cause the cams to retard timing and loose power.

The y-pipe exhaust manifold is a common problem on theese and they crack and leak exhaust gasses out before the cat.

:banghead: Hi i was wondering what you have had done since the small slip in power at acceleration (like a miss.) and exhaust/gas smell with smoke visible from the muffler. The car also sounded loud.
I TOO AM HAVING THE SAME PROBLEM AND IT IS DRIVING ME CRAZY, HAVE YOU HAD THE VEHICLE FIXED SINCE THIS POST
AND IF YOU HAVE HAD IT FIXED WHAT EXACTLY DID THEY OR YOURSELF REPLACE? THANK YOU FOR YOUR INPUT.

Initially, I was experiencing a small slip in power at acceleration (like a miss.) Soon after this happened the car began to roughly idle when coming to, or at a stop.
I also experienced an exhaust/gas smell with smoke visible from the muffler. The car also sounded loud.

The car still was a bit louder than it should have been but ran fairly well for a while; nevertheless, the problem was back within the week and has the same difficulty getting up to speed (meaning 40mph) with rough idling and visible gassy smelling smoke.

I'd definitely check your exhaust for a break...typically the down tube between the manifold and the cat is where it breaks. You'll see a braided section where it is designed to flex, but it fail eventually.

As for the smelly exhaust and poor acceleration, I'd suggest a good tune up.

New plugs, cap & rotor contact cleanup or replace, and timing check. If it's been a while, this alone can significantly improve idle and performance as many miles cause oxidation of the cap/rotor contact surfaces. Spark plugs wear down, gaps increase, and performance drops. I'd even suggest a new ignition coil...they're not expensive and if yours has abt 150k miles it may be ready to give up, leaving you stranded.

If the timing belt hasn't been replaced, it should be along with the accompanying oil seals.

Tranny fluid replacement.

EGR and PCV valve clean.

Hope this helps!

Thanks for the input , i had a good hunch i was going to have to do all this eventually your reply was a great help. thanks again.