Michelle.....define the term surge in more detail....

At start/idle the engine rpm raises and lowers ??? how much ?? it does this about 4 times and then quits ???

Here is more detail: I start the truck,by the time i put on my seat belt, you can hear the engine rpm's fluctuating (surging) the tach will go from just below 1(usually where it sits at an idle) to approx 2 or so and back down again. It will do this sometimes only twice and then quit or sometimes it will do it 4 times and quit or by then i get annoyed and put the truck in gear. It doesnt always do it.
Here is what happened after I left the repair shop the other day. The shop had it started a few times and had no surging. I head for home which is about 30 km's away(sorry dont know miles). I stop in the next town (15km's)to get some grocery's, chat with a friend etc. Maybe parked for 20 minutes. Get in truck start it up, it surges. Drive home. Park truck. Start it up again. No surging. Parked it all night. Started it up next morning no surging. It doesnt seem to matter how much fuel i have in the tank or whether I am on a flat surface or a bit of an incline.

Hope this explains it better.
Michelle

Sure sounds like an intake manifold gasket leak, having experienced this problem twice. In any case, it's easy to check - with the engine running, spray carb cleaner or similar flammable aerosol around the margin of the intake manifold. If the cleaner gets sucked into the manifold via a gasket leak, there will be a sudden change in rpm. Sometimes you can even hear the leak hissing.

And it's a common problem on that vintage 'Zu.

[quote]Sure sounds like an intake manifold gasket leak, having experienced this problem twice. In any case, it's easy to check - with the engine running, spray carb cleaner or similar flammable aerosol around the margin of the intake manifold. If the cleaner gets sucked into the manifold via a gasket leak, there will be a sudden change in rpm. Sometimes you can even hear the leak hissing.


Thanks for the input but have already replaced the intake gaskets a few months ago.

Michelle <img src="/forums/images/graemlins/cheers.gif" alt="" />

Michele....give the suggestion about the carb cleaner or similar aerosol a try....I got some feedback some another forum and everything points to a leaky intake problem or EGR valve sticking or leaking....
New gaskets can be installed and leak!!!!! If NO change in RPM with the spray...then you can surely say it is not a intake gasket issue....

Becareful not to spray on the exhaust system...the spray is flammable and dangerous!!!!

For what what it's worth I had a surge issue when the TPS on my 2.6 was out of wack. It wasn't much. Just a searching effect maybe 200-300 rpm up and down for three or four times before it settled down; like the ecm was trying to figure out how much fuel the engine needed.