My nephew's 1995 Sportage, DHOC, 5 speed, has lost a lot of power in 4th and 5th gears. We just installed a new timing belt and water pump a couple of weeks ago and every thing was fine except for a moderate exhaust leak. At the same time we installed a new timing belt on my 2001 Sportage and both vehicles ran fine.

I discovered that I had had a slight Brain-Fart and failed to perform the last step in the porcedure which is to rotate the exhaust cam to the S mark and then tighten the tensoner. We corrected that last weekend. We at that time installed new plugs in the 1995, the center electrode on the old plugs was burnt off. When re restarted the 1995 all appeared well but we later discovered that there was a serious loss of power in 4th and 5th gears. The afore mentioned exhaust leak is much worse and it is located at the flange between the header and the down-pipe which is about two inches above the O2 sensor.

Would this leak cause the O2 sensor to indicate a lean condition and make the mixture rich causing the loss of power. Fuel economy has fallen from 27mpg to about 17mpg.

I would say yes..that exhaust leak can definitely fake out the O2 sensor.

The Sport just went to the muffler shop and had the leak repaired so we should know soon if that was the problem.

I thought they only made the DOHC from '96 on up. The 95's were supposed to be single overhead cams.

Not true, this is an early 1995 purchase new by my nephew for $12,000, it has been a great car and now has 120,000 miles on it. It look very much like my 2001 under the hood with some obvious exceptions, and insted of having a cast exhaust manafold it has a tubular header.

Update: The exhaust leak was repaired yesterday and did not improve the performance of the Sport. Replaced the coil packs, plugs wires, and plugs, no change. One of the questions is if there is a bad connection on the coolent temp sensor of a failed sensor what would the effect be on the performance of the engine. My nephew describes the engine sound, now that the exhaust leak is fixed, as if there is bad valve rattle.

The 1995 DOHC is probably OBD1 so I don't know if it has a knock sensor.

Any insights from any of you will be appreciated. <img src="/forums/images/graemlins/confused.gif" alt="" /> <img src="/forums/images/graemlins/confused.gif" alt="" /> <img src="/forums/images/graemlins/confused.gif" alt="" />

yes, it absolutely will, but, as far as i know, only in the auto tranny, not the manual. it can keep it from shifting into 4th gear, ruining your mileage, but not necessarily power. <img src="/forums/images/graemlins/zombie.gif" alt="" />

i don't know enough to say for sure, but it sounds as though your exhaust timing could be the culprit.

We worked on it again Saturday and the engine runs great but under load it will not go above 4000 rpm. The engine is smooth and no valve rattle, I think that it is a fuel problem. The fuel filter has been in for at leat 60,000 miles and the injectors had not been cleaned for some time. The fuel filter is connected by one Banjo fitting and one flair fitting.

Check the fuel injector tube. It should open from the front. See if the gas is dirty. This happened to a '95 I used to own. Also, have you checked the compression?

Have not checked the compression but this problem started suddenly and has every appearence of being a fuel starvation problem.