My Engine Runs Rough When It Gets Hot But Ok When Cold

Reader Question

I own a Chevy S10 and have my friends here that is the 2001 version and it has the plastic intake air set up on it, it is a 2.2 liter and here is what is happening to it. When you start it up cold it runs well and has all kinds of power, but when it start to get warm the engine loses power and has a hard time idling. I have a Haynes manual, but it does not go into enough detail.

I have been working on cars and trucks for years but they all have many problems and I need to know the areas to check to narrow down the problem and find the cause, in the book it states it could be the intake manifold, or even the head gasket, I am hoping it is not the head, but if you would be so kind as to direct me I would most grateful and would do my part to refer business to you, word of mouth sell faster the adds and every one can use the business.
Thank you Chris


Hey there Chris,

This is what I would do if you came to my shop.

1. Read the computer codes and investigate any trouble code that is stored in memory

2. Check the fuel pressure at the engine with a manual fuel pressure gauge (kind sounds like you have weak fuel pressure)

3. Check for a vacuum leak under the hood (listen for a hissing noise with engine running, check all rubber vacuum hose connections)

This should help you narrow down which direction to go in.

You can sometimes bang on the bottom of the fuel tank with your fist or small block of wood with engine running and problem happening…if the engine runs better or changes in anyway, I would suspect a fuel pump issue.

Austin Davis


Reader Follow Up

I was checking it today and did find some hoses with cracks but I also used a spay bottle and had it running and found shorting in #4 plug wire, I had a felling it was electrical because of the symptoms. I have a fuel pressure test and can also check the pressure.

Thank you for the insight, I will let you know how it goes.

Posted in: Running Problems

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